recovered lost dropBomb() code

lines 81-84 were accidentally lost in a previous merge conflict
resolution
fixed bug where enemy bombs were misaligned with the swarm
Weapon, Cannon

Changed double-barreled-gun.js into cannon.js, changed weapon's variable
names
Added debugging rectangle to utils.js
Added basic collision

A spatial partitioning implementation using quadtrees.
Collision.js still needs work.
Improved debugging rectangle util
Added AOE , collision detection to projectile

new property : AOE,
also added functionality to allow visual debugging and basic collision
detection
Updates to files in order to implement collision

All colliding objects are held in the array Game.colliders.
Each colliding Destructible should be added to this array on creation
First pages commit
Update index.html
Merge branch 'gh-pages' of https://github.com/Stopa/Mobile-Defence-Fortress into gh-pages