openspace: init at 0.11.1

This adds a new package: OpenSpace, an open source astrovisualization
project, and one of its dependencies: SOIL (Simple OpenGL Image
Library).

This kind of works for me, but please note that this build is not very
usable for now. This is a first attempt. Also, Linux doesn't seem to
be well supported upstream, hence the various patches (I will open an
issue upstream to discuss them).

Squashed commits:
openspace: fetch upstream glm "patch"
openspace: add missing dependency (libXxf86vm)
soil: mesa -> mesa_noglu