Starting weston next branch

Hi,

We've talked a bit about branching 1.0 and starting new development on
master, and there's definitely a number of features already waiting to
be merged: Anders headless backend, Tiagos xwayland work, Scotts
minimize etc work, Johns GLES2 patches etc.

However, instead of branching of 1.0 development, I'd like to make a
'next' branch for now, where we can integrate new features for later.
The master branch continues to be for 1.0.x releases, as we focus on
improving documentation and fixing bugs a little longer.

Kristian