Fix gpu deforms
#define OVERRIDE and FINAL for msvc
Make the GL3 renderer's R_SortDrawSurfaces() emulate a stable sort

The vanilla renderer uses a stable sorting algorithm for R_SortDrawSurfaces
This has the nice property of preserving the front to back bsp traversal order
Enable parallel builds for MSVC
Fix some potential buffer overflows
Fix nettle URL in build.sh
Preserve g_layouts across map changes.

This needs to be properly fixed. It's a mess…
Merge branch 'master' into training