run multiple update and collide steps for the bullet
change tile hitbox to tile entity since hitbox is only a property of returned object
change indent
update bullet collisions to return normal and points that are on the surface of the collided hitbox
Merge pull request #2 from jpmit/fixcollision

Fixcollision
updated projectile handling to handle tunneling
updated npm modules
implemented triple jump support
add water tile and modified gravity test
added water physics and basic ladder/rope support
fix bug in position updating: use Math.round rather than Math.floor