Fixed Bug #679589 "Use Action Appearance not supported for GTK 2.12 but added to widgets in Glade 3.8.2"
Made sure use-action-appearance is not saved if there is no action defined

Conflicts:
	plugins/gtk+/glade-gtk-activatable.c
	plugins/gtk+/glade-gtk.c
	plugins/gtk+/gtk+.xml.in
Removed activatable_parse_finished()
Added build/mingw-w64 directory with script tp cross compile and create windows installer using nsis
Ported build for mingw to 3.8 branch
Revert "Removed activatable_parse_finished()"

This reverts commit 12ad1a8227348717dc00f9daea480363c2bc78b0.
Fixed bug in button properties sensitivity
Rolling 3.8.3