core (Cagou): add debug log for widget visibility + ignore_missing: - debug log are now use to show which widget are made (in)visible, and to show the list of currently visible widgets - "ignore_missing" can be used in _removeVisibleWidget when we can expect that a widget is missing in visible widgets list.

include MANIFEST.in cagou/VERSION
global-include *.py
global-include *.ini
global-include *.po *.mo
global-include CHANGELOG COPYING* INSTALL README*
global-include *.sh
global-include Makefile *.rst *.bat
include android
include service
include bin
include doc
global-exclude *.un~