org.freedesktop.compiz.*
   /org/freedesktop/compiz/*
to:
    org.compiz.*
   /org/compiz/*

schemas on build on the schema generation area so that the tests
can read them.

It was a broken hack for a problem that didn't exist

Install plugin images and data to separate plugin-specific subdirectories (so that plugins can't overwrite other plugin's data). Also fix typo in CompizGenInstallData.cmake