Initialize accessibility support on clutter_init

Initialize accessibility support on clutter_init

Initialize the accessibility support calling cally_accessibility_init

Take into account that this is required to at least be sure that
CallyUtil class is available.

It also modifies cally_accessibility_module_init in order to return
if the initialization was fine (and the name, removing the module word).

It also removes the gnome accessibility hooks, as it is not anymore
module code.

Solves CB#2098