Collision detection version 1 - Bounding Boxes

Collision detection appears to be working, refinement and testing will
occur tomorrow when I start to implement a proper movement system.
Old updates to the platformer
Basic damage detection

Basic damage detection with the player and enemy. Added base for
projectile class.
Made is so that, finally, everything is now using floats! ("hooray!")
Fixed some issues preventing compilation on linux, for example non-const lvalues being returned / used in some of the bounding box methods were causing problems apparently covered up by MSVC
Collision detection tests

Played with projectiles a little, organisation and some other things!
Fixed a bug where I was destroying textures too early, added implementation and collisions between the map for enemies and projectiles.
Collision detection between projectiles, enemies and players implemented. Added some more parts to the level.