fix displaying result of update check during Beremiz startup

fix pylint warning '(no-init) Class has no __init__ method'

fix pylint error "(undefined-variable) Undefined variable 'X'"

fix problem happend when tests are running under python-coverage

$ python-coverage run ./tests/tools/test_application.py

Exception while connecting LOCAL://!
Traceback (most recent call last):
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 1753, in _Connect
self._SetConnector(connectors.ConnectorFactory(uri, self)
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 1702, in _SetConnector
if connector is not None:
PyAssertionError: C++ assertion "m_window" failed at ../src/gtk/dcclient.cpp(2043) in DoGetSize(): GetSize() doesn't work without window

fix pylint error '(too-many-function-args) Too many positional arguments for function call'

fix pylint error '(import-error) Unable to import X'

fix pylint error '(no-self-argument) Method should have "self" as first argument'

fix pylint error "(no-name-in-module) No name 'X' in module 'Y'"

fix pylint error '(bad-except-order) Bad except clauses order (X is an ancestor class of Y)'

fix pylint warning "(no-value-for-parameter) No value for argument 'X' in function call"

fix problems with unconnected input of InOut function variables and
enfoce InOut variables to be connected for functions and function blocks

fix error for functions with VAR_IN_OUT

The problem was found by pylint '(used-before-assignment) Using variable "X" before assignment'

fix pylint warning '(unidiomatic-typecheck) Using type() instead of isinstance() for a typecheck'

fix pylint warning '(misplaced-bare-raise) The raise statement is not inside an except clause'

fix format string argument error found by pylint '(too-many-format-args) Too many arguments for format string'

fix pylint warning '(wrong-import-position) Import "import X" should be placed at the top of the module'

fix pylint warning '(import-self) Module import itself'

remove old code useless code found by pylint "(unnecessary-pass) Unnecessary pass statement"

fix error found by pylint 'W0104(pointless-statement) Statement seems to have no effect'

fix pylint warning "(undefined-loop-variable) Using possibly undefined loop variable 'X'"

fix pylint warning 'C0112(empty-docstring) Empty function docstring'

fix pylint warning "(relative-import) Relative import 'Y', should be 'X.Y'"

fix pylint warning '(dangerous-default-value) Dangerous default value {} as argument'

fix pylint warning '(old-style-class) Old-style class defined.'

This warning is ignored for classes from PyJSLib, because library
overrides base object class.

fix pylint warning '(unused-import), Unused import connectors'

fix typos

comment out unused code SFC_Step.RefreshBoundingBox()

explicitly mark unused variables found by pylint with _ or dummy

pylint don't ignores unused variables with '_' in the name, even when
they are started with '_'. This bug is already fixed upstream, to fix
this in all versions of pylint custom dummy-variables-rgx is used
'_+$|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)|dummy'