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).