add utils for porting maps from sven -> HL

WIP and relies on other code edits not committed (changing limits and disabling the nav mesh generation).

new options:
- Select all/connected faces of this texture (for mass scaling to fix "AllocBlock full" errors)
- Subdivide face (for fixing max surface extents errors)
- Fix bad surface extents (scale or subdivide bad faces globally)
- downscale invalid textures (wip, only affects face coordinates and does nothing to the texture or wads)
- delete OOB data (deletes all BSP data outside of the +/-4096 map boundary. When combined with map merging it can be used to compress +/-32k sven maps into the smaller HL map boundaries. Select worldspawn to see the map boundaries as a green box)
- apply worldspawn transform (like the "move" command from the commandline. Worldspawn can also be transformed again using the transform window).