Rework ghostview generator, not finished but i can see valgrind_manual.ps quite correctly
- We don't use libqgs anymore but libgs directly
- We don't use an out of process executable anymore to talk to libqgs

Using libgs is a bit cumbersome (only one gs instance per process) and almost no other gs viewer does it, but if you look at kghostview code it's full of X black magic, so going the libgs path feels better for my sanity and for portability