DD64 hotfix

Added extra supply crates before bossfights
Medkits heal from 30 to 50
Fixed Chieftain boss triggering ground slam when colliding with the arena's columns mid-air
Fixed explosions not working properly and horrid weapon jitter when setting the fps limit higher than 60.
Fixed Vsync options resetting to enabled when the options menu was opened
Fixed an interaction bug related to exiting the level while being on the Boat's .30 cal mount
Fixed mutations not being saved if the Boat's .30 cal upgrade was active