Moves volumetric lighting post effect to a separate shader so it can be used as a separate post effect (which utilizes a half sized RT).
Adds that all fog related effects get modulated according to the light buffer and/or overall luminance.
* Disables back face culling for shadow rendering (less swiss cheese shadows).
* Tweaks various fog related parameters and tweaks some things on shader side.
Add VSync option
Copy and pasting, eh?
Merge pull request #708 from socram8888/vsync

Add VSync option
Initial work on new light propagation implementation
Made the BatchPropagation system generic so it can be used for both light and sunlight (and other things too)
* Integrated new batch light propagation system
* Removed the need to provide the old block when setting a new block (all block changes will need to be made on main thread)
* Removed unneeded setBlockForced method
* setBlock() now returns the previous block type
* Disabled grass growth and liquid simulations pending rewrite for new threading
Merge branch 'multiplayer' of git@github.com:MovingBlocks/Terasology.git into multiplayer
Checkstyle fixes.
Merge pull request #706 from socram8888/multiplayer

Optimizations in chunk tree generation
Checkstyle fixes.
Removed light propagation steps from chunk generation.
Whenever a chunk is loaded, propagation is checked for the edges of the chunk to correct for changes since it was last loaded.
Some performance improvements to batch light propagation - combines bound checks with fetch operations.