protocol: Add release requests for wl_pointer, wl_keyboard, and wl_touch

We missed destroy requests in the 1.0 protocol and since the scanner
generates local-only *_destroy requests in that case we can't add
destroy requests without breaking protocol.  A client needs to verify
that the server provides a version 3 seat to use the protocol destructor
so the name needs to be something else than wl_*_destroy.

v2 (Rob Bradford): Rebased, bumped the protocol versions and added since
attributes to the requests.
scanner: Emit wl_*_destroy stub even if interface has a destructor

If an interface has a destructor but no 'destroy' method we used to
not emit a destroy method.  Now with the fix for missing destroy
requests for wl_pointer etc we need to emit the local wl_*_destroy
always.
configure.ac: Bump version to 1.2.90 for master branch
wayland-server: Fix a uninitialized warning from clang

This warning is unnecessary, since the pointer in question is only used
for pointer arithmetic, but setting it explicitly to NULL doesn't hurt.
wayland-server: Document wl_signal
utils: tweak wl_list for better doxygen output
wayland-server: Add a wl_resource_for_each_safe macro

A version of wl_resource_for_each that is safe for iteration when items
in the list are removed.
gitignore: add ./compile

./compile is a GNU autotools helper script and should be ignored by git
wayland-server: Document wl_listener

This patch takes Kristian's comments into account, adding a demonstration and
giving a more thorough idea of how wl_listener is used.
utils: Reference some useful methods in wl_signal's doxygen

This commit adds a bit more detail on the lifecycle of a signal.
utils: Add doxygen for wayland-util.h

This is needed for doxygen to generate output for macro definitions, such
as wl_container_of, that are contained by this file. Classes like
wl_list would be documented regardless.
wayland-server: Improve wording for wl_signal_get's doc

The old description was a bit vague; this commit hopefully improves
describing what is returned.
doc: Include wayland-util.* for doxygen output

This commit creates a shared file list that is included by both the
client and the server for the XML Makefile targets, as classes within
util are used by both the client and the server.