Mark as user actions undo and redo
Updated Serbian translation
Update python tests for Python 3

print was changed from a statement to a function in 3.0, but as simple
print calls, this syntax is compatible with both 2.x and 3.x.

Signed-off-by: Yaakov Selkowitz <yselkowitz@users.sourceforge.net>

https://bugzilla.gnome.org/show_bug.cgi?id=691268
Completion: clean header inclusions