v0.9.34 beta 2

Beta build: 0.9.34 beta 2.

Fixes

• Compiled shaders no longer thrown away by updates: the shader cache was cleared on almost every engine update, even ones that didn't touch the shader compiler, so every area stuttered again after updating. It is now kept unless the compiler itself changes. Your current cache is kept by this update.
• Shorter stutters in new areas: new shaders compile on more threads at once (half your CPU threads, was at most 4).

Note: 0.9.32 moved the cache to user\cache, so the shaders compiled before that are not used anymore; the first trip through each area compiles them once more, and after that they stay.