Merged dblbuffering into trunk

Hello!

I merged dblbuffering into trunk (r30142) so we should expect less
flickering in AbiWord from now on. I also created this page [1] on
wiki, briefly explaining how it works and how one could take advantage
of this code.

I hope little or no bugs will emerge from this. However, I will
quickly fix anything that shows up, so please let me know if you
notice anything wrong.

[1] http://www.abisource.com/wiki/Write_flickering_free_code

Cheers!
Andrei
Received on Tue Aug 9 00:38:44 2011