Wed, 21 Jun 2017 17:08:52 +0300add button to ForceVariableDialog to toggle forced boolean value
Andrey Skvortsov <andrej.skvortzov@gmail.com> [Wed, 21 Jun 2017 17:08:52 +0300] rev 1701
add button to ForceVariableDialog to toggle forced boolean value

Button is added only for boolean variables.

Tue, 20 Jun 2017 18:57:29 +0300fix problem with hidden FindInPou dialog with wxPython 3.0 on Windows
Andrey Skvortsov <andrej.skvortzov@gmail.com> [Tue, 20 Jun 2017 18:57:29 +0300] rev 1700
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.

Tue, 20 Jun 2017 17:01:19 +0300enable non-latin variable descriptions in CodeFileEditor
Andrey Skvortsov <andrej.skvortzov@gmail.com> [Tue, 20 Jun 2017 17:01:19 +0300] rev 1699
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)

Tue, 20 Jun 2017 16:36:17 +0300disable empty coils and contacts in LD/SFC editors
Andrey Skvortsov <andrej.skvortzov@gmail.com> [Tue, 20 Jun 2017 16:36:17 +0300] rev 1698
disable empty coils and contacts in LD/SFC editors

Closes #30