Fix crash in runtime if PSK secret is missing

./Beremiz_service.py -s $PWD/psk2.txt -n beremiz /tmp/beremiz
Beremiz_service: 1.2-1378c18402c3+

Traceback (most recent call last):
File "./Beremiz_service.py", line 511, in <module>
ensurePSK(servicename, PSKpath)
File "/home/developer/WorkData/PLC/beremiz/beremiz/runtime/Stunnel.py", line 32, in ensurePSK
PSKgen(ID, PSKpath)
File "/home/developer/WorkData/PLC/beremiz/beremiz/runtime/Stunnel.py", line 23, in PSKgen
call(restart_stunnel_cmdline)
File "/home/developer/WorkData/PLC/beremiz/beremiz/runtime/spawn_subprocess.py", line 116, in call
pid = posix_spawn.posix_spawnp(cmd[0], cmd)
File "/home/developer/.local/lib/python2.7/site-packages/posix_spawn/_impl.py", line 120, in posix_spawnp
return _posix_spawn(lib.posix_spawnp, *args, **kwargs)
File "/home/developer/.local/lib/python2.7/site-packages/posix_spawn/_impl.py", line 111, in _posix_spawn
_check_error(res, path)
File "/home/developer/.local/lib/python2.7/site-packages/posix_spawn/_impl.py", line 10, in _check_error
raise OSError(errno, os.strerror(errno), path)
OSError: [Errno 2] No such file or directory: '/etc/init.d/S50stunnel'

Update build instruction for BACNet in README

in r3189 Steve added new feature to bacnet-stack: network port - to
access configuration and properties of network ports of a device.
https://sourceforge.net/p/bacnet/code/3189/

It's not implemented by Beremiz.

Replace md5 module with hashlib

fix following pylint error:

************* Module connectors.ConnectorBase
connectors/ConnectorBase.py:7: [W1648(bad-python3-import), ] Module moved in Python 3
************* Module runtime.PLCObject
runtime/PLCObject.py:33: [W1648(bad-python3-import), ] Module moved in Python 3

Remove execute attributes from runtime/PLCObject.py

Fix typo

Fix various pylint and pep8 errors

Check basic code-style problems for PEP-8
pep8 version: 2.4.0
./connectors/PYRO/__init__.py:57:43: E261 at least two spaces before inline comment
./connectors/SchemeEditor.py:29:21: E128 continuation line under-indented for visual indent
./controls/IDBrowser.py:101:23: E127 continuation line over-indented for visual indent
./controls/IDBrowser.py:102:23: E127 continuation line over-indented for visual indent

Check for problems using pylint ...
No config file found, using default configuration
pylint 1.9.4,
astroid 1.6.5
Python 2.7.16rc1 (default, Feb 18 2019, 11:05:09)
[GCC 8.2.0]
Use multiple threads for pylint
Using config file /home/developer/WorkData/PLC/beremiz/beremiz/.pylint
************* Module connectors.PYRO_dialog
connectors/PYRO_dialog.py:9: [W0611(unused-import), ] Unused import wx
************* Module connectors
connectors/__init__.py:32: [W1652(deprecated-types-field), ] Accessing a deprecated fields on the types module
connectors/__init__.py:32: [C0411(wrong-import-order), ] standard import "from types import ClassType" should be placed before "from connectors.ConnectorBase import ConnectorBase"
************* Module connectors.PYRO.PSK_Adapter
connectors/PYRO/PSK_Adapter.py:7: [C0411(wrong-import-order), ] standard import "import ssl" should be placed before "import sslpsk"
************* Module connectors.SchemeEditor
connectors/SchemeEditor.py:29: [C0330(bad-continuation), ] Wrong continued indentation (add 1 space).
wx.ALIGN_CENTER_VERTICAL),
^|
connectors/SchemeEditor.py:42: [W0631(undefined-loop-variable), SchemeEditor.__init__] Using possibly undefined loop variable 'tag'
************* Module runtime.WampClient
runtime/WampClient.py:138: [W1612(unicode-builtin), WampSession.onJoin] unicode built-in referenced
runtime/WampClient.py:154: [W1612(unicode-builtin), WampSession.publishWithOwnID] unicode built-in referenced
runtime/WampClient.py:346: [W1612(unicode-builtin), PublishEvent] unicode built-in referenced
runtime/WampClient.py:351: [W1612(unicode-builtin), PublishEventWithOwnID] unicode built-in referenced
runtime/WampClient.py:31: [W0611(unused-import), ] Unused str imported from builtins as text
************* Module runtime.PLCObject
runtime/PLCObject.py:35: [W1648(bad-python3-import), ] Module moved in Python 3
runtime/PLCObject.py:35: [C0411(wrong-import-order), ] standard import "import md5" should be placed before "from six.moves import xrange"
runtime/PLCObject.py:36: [C0411(wrong-import-order), ] standard import "from tempfile import mkstemp" should be placed before "from six.moves import xrange"
runtime/PLCObject.py:37: [C0411(wrong-import-order), ] standard import "import shutil" should be placed before "from six.moves import xrange"
runtime/PLCObject.py:38: [C0411(wrong-import-order), ] standard import "from functools import wraps, partial" should be placed before "from six.moves import xrange"
************* Module runtime.Worker
runtime/Worker.py:12: [W1648(bad-python3-import), ] Module moved in Python 3
************* Module runtime.spawn_subprocess
runtime/spawn_subprocess.py:125: [C0325(superfluous-parens), ] Unnecessary parens after 'print' keyword
runtime/spawn_subprocess.py:130: [C0325(superfluous-parens), ] Unnecessary parens after 'print' keyword
runtime/spawn_subprocess.py:125: [E1601(print-statement), ] print statement used
runtime/spawn_subprocess.py:130: [E1601(print-statement), ] print statement used
************* Module controls.IDBrowser
controls/IDBrowser.py:101: [C0330(bad-continuation), ] Wrong continued indentation (remove 5 spaces).
if self.isManager
| ^
controls/IDBrowser.py:102: [C0330(bad-continuation), ] Wrong continued indentation (remove 5 spaces).
else dv.DATAVIEW_CELL_INERT),
| ^
************* Module Beremiz_service
Beremiz_service.py:34: [W0611(unused-import), ] Unused import __builtin__

Fix invalid python3 syntax

Syntax checking using python3 ...
Python 3.7.2+
File "./connectors/PYRO/__init__.py", line 76
except Exception, e:
^
SyntaxError: invalid syntax

Syntax error in ./connectors/PYRO/__init__.py
File "./connectors/PYRO/PSK_Adapter.py", line 40
except ProtocolError, x:
^
SyntaxError: invalid syntax

Syntax error in ./s.py
File "./runtime/Worker.py", line 67
raise _job.exc_info[0], _job.exc_info[1], _job.exc_info[2]
^
SyntaxError: invalid syntax

Exclude pyjslib.py from python3 syntax correction check

pyjs doesn't support python3 and it's unmaintained.
async is a new keyword introduced in python 3.7.

./tests/tools/check_source.sh
Syntax checking using python3 ...
Python 3.7.2+

Syntax error in ./runtime/Worker.py
File "./svgui/pyjs/lib/pyjslib.py", line 24
def import_module(path, parent_module, module_name, dynamic=1, async=False):
^
SyntaxError: invalid syntax

revert occasionally committed changed first_steps project.

project was changed by commit:
update translations from https://www.transifex.com/beremiz/beremiz-ide (756d02cf78db)

Merged in masterschlumpf/beremiz/generate-button (pull request #38)

"Generate Prgram" button

Approved-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>

Create a "Generate Program As..." menu to make the "Generate Program" toolbutton even more useful.

The behaviour is the same as "Save" and "Save As...". Now "Generate Program" uses the last filename
if known and "Generate Progam As..." asks every time.

Add "Generate Program" to toolbar in PLCOpenEditor standalone mode.

Currently you can find the "Generate Program" action only in the file menu,
but this action is very often used in standalone mode, so I added toolbuffon.

Merged search in CTN branch

Finished adding search in python and C files. Stripped debug code and useless comments. Close branch

WIP adding searching capabilities in python files. was done :
- added search in body of Code File Tree Nodes (moved editor code so that we CTN search can have the same sections text layout as editor to search in)

WIP adding searching capabilities in python files. was done :
- added search in global variables used by Code File Tree Nodes