make rockets uncollidable with their creator and their creator's bullets
fix possible memory leak on weapon change
fix test
fix performance test
unfinished collisionfilter as instance
make collisionfilter a member
remove unused code
Merge branch 'master' into fix_rocket_explode_directly

Conflicts:
	src/gamescenario.h
Merge pull request #329 from voxelinc/fix_rocket_explode_directly

Fix rocket explode directly - Enum will be fixed in #336