Added Lerpable interface +
lerp function for classes implementing Lerpable.
palette is now a UIList
nodes can be collapsed/expanded using right mouse click
copy subtrees using SHIFT
link subtrees using SHIFT, does not work fully
Merge remote-tracking branch 'upstream/develop' into behavior
updated to latest changes
Tasks are now injected
Merge remote-tracking branch 'upstream/develop' into behavior

Conflicts:
	engine/src/main/java/org/terasology/logic/players/MenuControlSystem.java
Refactored headless environment
Merge remote-tracking branch 'movingblocks/develop' into develop
Fixed style warnings
Moved Profiler to src/dev
Refactored WorldAtlas into interface and implementation
fixed bt editor layout
editor now opens using F5
refactored Task and Interpreter
Stopping a task now stops all tasks, that were started by the task.
Merge remote-tracking branch 'upstream/develop' into behavior

Conflicts:
	engine/src/main/java/org/terasology/logic/behavior/nui/BehaviorTreeEditorSystem.java
Remove lwjgl dependencies from Texture
added some icons
Merge pull request #859 from synopia/behavior

added some icons