Readibility changes to RenderableWorldImpl: renaming of variables and methods.
RenderableWorldImpl: extracted variables from loops and compacted methods where possible, reviewed and refactored logic where useful, added a few class-level static final variables. Augmented the interface Chunk to include hasMesh() and hasPendingMesh() methods. RenderableChunk implementation changed accordingly.
RenderableWorldImpl changes. Addressed issues mentioned so far: public static variables made private for the time being; config-requiring static variables made non-static, as requested by immortius; small compromise/temporary changes to the comparators and the squaredDistanceToCamera() method for a small performance improvement.
Merge PR #1459 by @emanuele3d - rendering tweaks