Fixes for #377
Recycling of entity ids should now work - forgot to return recycled entities
Added some debugging code to show active entities
Fixed the entity reference cache - it now correctly will drop unused references during garbage collection
Changed block entity mode to default to ON_INTERACTION, so normal blocks are not retained indefinitely as entities.
Merge branch 'develop' of git@github.com:MovingBlocks/Terasology.git into develop