Dan Nicholson authored Feb 13, 2010 and Peter Hutterer committed Feb 15, 2010

Currently the config and InputClasses are merged together so that the
options from the config backend have the highest priority. This is bad
since it means options such as a default XKB layout set by the backend
cannot be changed by the user.

This patch changes order of precedence to be:

1. xorg.conf
2. xorg.conf.d (later files have higher priority)
3. config backend

In order to allow this ordering, the config parsing has been changed to
read the xorg.conf.d files before xorg.conf. This has the consequence
that the core device picking which looks for the first InputDevice may
not find it in xorg.conf.

Signed-off-by: Dan Nicholson <dbn.lists@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>