Cap vertical look to +-90deg. Save mouse position when locking
Q3BSP loading mostly working

Some textures are missing or wrong, but they are actually loading.
This needs a modified SFML that can load compressed image files from
memory.
BSP parser beginnings

Assimp is far too limited to use as the map loader (metadeta is ng,
textures are too much work)
Vertex and indices work. Normals appear partially working
Quake3 demo pak added.

Also improved j7Model's texture loading.