Multiple input resource support (v2)

[Rob Bradford]

Hi folks,

The wayland protocol lets you support multiple wl_pointer/wl_keyboard/wl_touch
in a client - unfortunately Weston makes the assumption that there is only one
input resource of a given class. These patches support the multiple resources
and are a key step in the enabling of libraries like Clutter-GTK where we
combine two wayland client library stacks together; each only vaguely aware of
the other.

This is a resend of the patches incorporating some bugfixes. There are 6
patches for weston and one remaining for Wayland (the other enabling patches
have already been integrated.)

Cheers,

Rob