[GT] Branches of the development tree

["João Costa" <joaocosta AT zonalivre.org>]

I noticed Thomas created an exp branch with the intention of using it
for trying out new stuff, while keeping the HEAD branch stable.

Ideally we would do use this method, there would be people testing
things under exp and every so often we'd do a new release and merge
that into head.

Unfortunately we just don't have an active enough community in GT, and
if things only get patched in the exp branch them most likely only the
author will use it until it gets merged to HEAD.

  I therefore feel tempted to apply the patches i've been sending in
the HEAD branch directly.