Meld 1.8.6.1: Restore'd former glory.

So i thought i'd try to maintain the GTK2 version.
This is the straight fix up of 1.8.6, only making it spit a .deb and adjust python.
However it wasn't as much of a learning curve as I had anticipated getting to know this project,
so the 1.8.6.2 branch needs testing, and feedback would be nice.