Also add SceneOpenGL::Texture class, based on GLTexture. Optimised for SceneOpenGL::Window, this adds support for loading from an X Pixmap, as well as taking advantage of texture_from_pixmap/shm when available. Automatically detects what texture target should be used, so be sure to enableUnnormalizedTexCoords() before painting.
Make SceneOpenGL::Window, BoxSwitchEffect, and ExplosionEffect use the new classes.
svn path=/branches/work/kwin_composite/; revision=645125
Add ExplosionEffect which makes the windows blow up into small pieces when they're closed.
In the future this could be used only when user kills (an unresponsive) window.
svn path=/branches/work/kwin_composite/; revision=643135
