MLG Fortress: April Updates

I was going to hold off until after I made some other updates this month, but there's been quite a bit of confusion on the new health canister system.

Major stuff

• Health canisters:
  • Drop more often
  • Max health limit of 37 hearts (from 90)
  • Any additional health gained by consuming canisters will be lost on respawning

Minor changes

• Improved knockback resistance with mobs. Mobs will no longer "freeze" when being hit.