- Added +FULLMASS.

Actors will be excluded from damage/radius thrusting of all sorts by
explosions or damage of any kind. They will also never deal impact
damage to other enemies, nor will they damage themselves from being too
close to a wall.
- Added DMSS_NOPROTECT.

Bypasses PowerProtection inventory items.
-Fixed: WhirlWind was still able to affect actors with the FULLMASS flag.
- renamed FULLMASS to DONTTHRUST.
Missing break in case NAME_FillColor

This caused weirdness with invulnerable monsters when their fillcolor was changed.
Merge branch 'master' of https://github.com/Gaerzi/zdoom
- fixed: P_RemoveThing must not remove owned inventory items.
- fixed last commit.