mki18n.py: generate messages.po (contains English strings in msgstr)

This po file is necessary because Transifex translation platform
automatically can only import PO files. Usually messages.pot is
enough.

add to i18n/README forgotten commands to add some XML schemes as source
for strings and update app.fil

Backout commit 92537ed because of writing localized string in node *.xml file

Backout changeset 92537edeb2052d53ba5cad8b6da8463dbc660bb1

fixes double mouse capturing after forcing variable in debug mode
this problem appears on Linux

fix bug with TextViewer instance in debug mode, appears after transferring new program on PLC
TextViewer isn't able to display debug values, so calling for this class SubscribeAllDataConsumers method causes error

fix build problem when make command have trailing whitespace(s)

whitespaces at the end are replaced with "", that causes make problem

add dialog "add program", that appears after creating new project
also, sets one task and one instance of created program in main project resource

fix i18n string selection for combobox generated from XSD

update Russian and French (Fabien M) translations
added Slovenian (Janez Pregelj) and Portuguese (Thiago Alves) translations

l18n: update messages.pot and app.fil

add l18n support to variable table in CodeFileEditor (python/C extension)

set project name and character set in generated messages.pot

close DurationEditorDialog on ENTER key

add button to ForceVariableDialog to toggle forced boolean value

Button is added only for boolean variables.

fix problem with hidden FindInPou dialog with wxPython 3.0 on Windows

FindInPou.IsShown() returned True, but dialog was hidden.
At same time On GNU/Linux with wxPython 3.0 there wasn't such problem.
So it's Windows specific.

enable non-latin variable descriptions in CodeFileEditor

fix following backtrace:

UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-7: ordinal not in range(128)
Traceback (most recent call last):
File "beremiz/editors/CodeFileEditor.py", line 610, in GetValue
return str(self.data[row].get(self.GetColLabelValue(col, False), ""))
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-7: ordinal not in range(128)

disable empty coils and contacts in LD/SFC editors

Closes #30

remove debug code

make all dialog have non-fixed size

this fixes the problem, that some controls may be hidden in some cases, because
dialog size is too small. This can happen when system fonts are bigger
than expected, default system them controls are bigger or if localized
strings are bigger than in English.

avoid infinite loop in search

for example following regexp '()' creates infinite list of result

make adjustable size of ArrayTypeDialog

fix problem with initial values for array of structures

for structures wrong empty repetition attributes were generated

add information about community support channel to Beremiz and PLCOpenEditor

cleanup wxHMI example

cleanup wxGlade example

add comments to wiimote example

fix running wxGlade on current Debian systems

wxGlade was moved from python import path to /usr/share/wxglade

rename text field in SVG graphic to match IEC code in svgui example

This caused svgui example to crash.

disallow setting IEC location addresses for TIME, DATE, DT and TOD variables

Size of these types is not defined and depends on the implementation
(IEC 61131-3 2.3.1).