[impdev] Time to prepare 1.3 beta 1!

[Jacek Antonelli]

Okay, here's what's going on at the moment:

* I can't repro the crash when changing Windlight settings (bug #198)
anymore, so I am going to assume it was fixed by the Snowglobe
rendering engine changes, unless someone reports it for the beta.

* I found a crash when changing antialiasing or anisotropic filtering
on Linux (bug #214), but it turned out to be a bug from SL 1.23.
Hopefully we can fix it before the 1.3 final, but I don't think it
should block the beta.

* I have merged some of Armin's "littlethings", and also created
issues for bugs reported in the merge test feedback thread, but there
is nothing more that needs to be fixed immediately, I think.

* I have updated the version number and pushed to my next branch.
Unless you guys encounter some serious issues, there will be no more
code changes for beta 1. So start your compilers! :D

* I still need to prepare the release notes, but please compile and
test now. Armin, since you will have to sleep sooner, you can upload
once you have finished compiling/testing. Don't wait for me to update
the release notes file.

That's it for now. Start compiling. Good luck, and "¡Viva la Imprudence!" ;)

- Jacek