Added play music node
Merge remote-tracking branch 'upstream/develop' into behavior
fixed miglayout and added @API to WorldAtlas
fixed music and sound node
added a global entity to run music node
Merge remote-tracking branch 'upstream/develop' into behavior
Only one global entity can be exist
Added AudioEndListener, so PlaySound/Music nodes switch from RUNNING to SUCCESS, once the sound/music ends.
Updated description in prefab
Merge remote-tracking branch 'upstream/develop' into behavior

Conflicts:
	engine/src/main/java/org/terasology/logic/behavior/BehaviorSystem.java
fixed bug in PostBeginSystems
AutoCreate to create a global entity for the default behavior tree
Removed API from WorldAtlas
ZoomableLayout can now zoom
Merge remote-tracking branch 'upstream/develop' into behavior
AudioEndListeners are now registered per sound/music play
removed log message
Added exception if entities are created during game intialisation.
Fixed errors when a ui layout asset defines layout hints for layouts that do not require them.
Added module access to TeraBullet's math util.
Added an onClosed() method to ControlWidget, to be called when a UI is closed.
World Atlas now generates a set of texture atlases. There is one for each module contributing block tiles - the individual tiles can be obtained through uris of the form <module>:terrain.<blockTileName>
Checkstyle fixes.
Fixed an issue with InventoryCell causing it never to display the question mark icon if no icon was specified.
Fixed transposed x and y coordinates
Drain input queues when changing state