Improves shadow rendering and changes the overall depth of field approach.

* Adds that the focus point for the depth of field effect is adjusted according to the players block camera target (with a range of 500 possible blocks/units
* Fixes incorrect depth range for the DOF effect
* Reduces shadow map size
* Disables linear sampling for the depth buffer (when did I enable this??)
* Adjusts shadow map x,y,z range to allow much more (blocky) detail
* Fixes absurdly wrong shadow/light camera position