Some cleanup
Merge pull request #613 from MarcinSc/multiplayer

Fixed shapes and texture coordinates for cable.
Simplified chunk load/unload process, removing the "ready" check on surrounding chunks.
Fixed deflate to happen before chunks being marked complete.
Added a system to detect problems with chunk load/unload events.
Fixed some bugs introduced with the cleanup.
Merge branch 'multiplayer' of git@github.com:MovingBlocks/Terasology.git into multiplayer
Adding screwdriver.
Merge remote-tracking branch 'upstream/multiplayer' into multiplayer
Gates can now be rotated and are placed based on placementSide.
Gates can now be rotated and are placed based on placementSide.
Signal on and signal off delay timer gates.
Signal on and signal off delay timer gates.
Rotating gates should now work ok.
Fixing gates blockTiles.
OnDelay and OffDelay gates also work.
Introducing signal network processing delays.
Introducing signal network processing delays.
Prefab inheritence should work properly.
Prefabs now support a "removeComponents" list property of components to remove from their parent.
Prefab loading is now handled much more by the asset system.
Fixed cleanup of memory when returning to the main menu, including a number of memory leaks.
Fixed a dubious location where multiple threads were changing an unsynchronized set.
Added logging when accessing unloaded chunks through the world provider (or with a height value out of range)
Renamed isBlockActive to isBlockRelevant
Added support for axis-specific symmetry to the Terasology blender plugin.
Improved symmetry handling in BlockShape.
Fix for a case where a chunk is loaded twice.
Trying to apply a better code to gates - gates can't change their signal more than configured time.