Visibility conditions added. It is possible to specify one enum property to be a visibility condition to an item of a shape
Merge branch 'master' of https://github.com/qreal/qreal
visibility conditions load fix
Visibility conditions: added support of int, bool and string types and different logical operators for them
Visibility conditions: rendering icons in palette
style fixes
Merge branch 'master' of https://github.com/qreal/qreal

Conflicts:
	qrgui/editorPluginInterface/sdfRendererInterface.h
	qrgui/umllib/sdfRenderer.h
Merge branch 'master' of https://github.com/qreal/qreal
fixed includes and some indents