Pass the current time to the aspects

Also make the current time available as a standard uniform in the
render aspect.

Change-Id: I163187c432cf32bf57d0c4bf4ee6b8e5d8aac42c
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Add an animated ribbon/wave example

This is an example that shows how to make a nice backdrop in the spirit
of the PS3's XMB background.

Change-Id: I32e83d92246b65ffb143884a1bac7a9b869c7989
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>