Adds support for deferred shading and light components.

* Removes hardcoded torchlight around the player (will be re-added later using the new light components)
* Restructured many things in the renderer to support deferred shading
* Adds support for light components (can be used to render an arbitrary amount  point and directional lights)
* Adds support for lit torches when throwing them around in the world (they're currently randomly colored - will change that within the next days)
* Fixes rendering of refractive and reflective surfaces (like water) during the night (bright things below the surface were not visible during the night because the refraction and reflection part was applied before the lighting part in the shader)
* Adds calculation of the inverse projection matrix to the perspective camera class
* Extended/overhauled debug shader stuff
* Removed sorting of alpha blend chunks - makes no more sense with the refraction implementation at the moment
* Overhauled and improved creation of FBOs
* Added support for an additional light buffer for FBOs
* Removed "sceneCombined" FBO and created a ping pong FBO for the "sceneOpaque" FBO instead

* Adds some minor cleanups here and there