Composite ClipNotify fix and expose event elimination (v3)

[ville.syrjala at nokia.com]

Turns out that v2 of this patchset has a problem with changing directly
between automatic and manual redirection modes.

Patches 5 and 6 fix those problems. I also removed some useless crap
from patch 3. The rest are unchanged from the last time I posted the
set.

I also pushed some new tests that excercise these codepaths for my test
tool here http://gitorious.org/vsyrjala/xwindow_check. It seems I
simply forgot to test those cases earlier.