use XDamage instead of polling

[GoogleCodeExporter]

It's wasteful for boblight-X11 to constantly poll the screen if nothing is 
happening. XDamage can be used to make sure we only run when needed.

The attached patch adds this option to boblight-X11.

(you can still use a polling mode with this patch, in case you have a buggy 
driver that doesn't report damage properly)

Original issue reported on code.google.com by pie...@ossman.eu on 24 May 2014 at 9:53

Attachments:

• 0001-use-XDamage-to-dynamically-track-screen-changes.patch