New build: lots of back end changes

Spend the last 3 days overhauling the complete prototype project by implementing a Game Manager with the Singleton pattern.

I think I managed to have it working in a way that makes sense without breaking things :D 

I also redoing the camera as I find it too twitchy too fast in the levels, I've only changed it in the first scene (the chess board) for now though.

Update: uploaded a new version with some minor changes:

- FPS counter is smaller now
- there's an issue with the camera that when you press the 'S' Key to walk backwards it spun around real fast, it is still somewhat present but hopefully less nauseating now!

KNOWN Issues:

- camera needs to be more sensitive when moving mouse (first level)
- pyramid and stairs/others not climable (not implemented yet)
- when pressing the 'S' key to walk backwards, the player spins out of control (all levels)
- no 'win' or 'level finished' condition implemented yet, need to press "Escape" to open the menu
- player can be pushed off the map (desert map) also there's no kill box so player keeps falling through