Disable xinput2 only for Cinnamon, not session-wide (moved from
cinnamon-session).  Programs that use Clutter-Gtk need to be able
to use it.

Fixes #2993
Fixes #2307
Fixes #2830
Fix a compiler warning
st-texture-cache: re-add load_file_simple as a convenience function
for load_uri_async.
st-texture-cache: Free memory
Cinnamon Settings: Fixed gaps/look of icon views