From: Couriersud
Subject: 32 & 16 bit versions of blendrect and blendline

attached are 32, 16 and 15 bit versions of the blendrect and blendline
functionality. There was an issue with the bresenham alg. in drawline
which I also fixed.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403358