cagou widget: don't add header_input systematically anymore: header input is often used in CagouWidget for e.g. filtering, but not always, and when it is not, it is weird and confusing to have a TextInput which doesn't do nothing. To avoid that, a new `use_header_input` bool attribute (set to False by default) has been added to CagouWidget.

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~