Create Headless and Base graphic-related assets

Inherit from BaseFont for common OpenGLFont behavior
Remove less-useful base classes

Make GLSLMaterial inherit from BaseMaterial
refactored code to use URI to types instead of full qualified class names.
refactored code to use URI to types instead of full qualified class names, part 2
Merge pull request #870 from msteiger/develop

Engine Tests: removed default module activation
refactored code to use URI to types instead of full qualified class names, part 3
Tidied up nodes, added some more essential nodes (counter, timer, wrapper).
First version of LookupNode, which runs another tree.
Minions in LAS now get a name.
Merge remote-tracking branch 'upstream/develop' into behavior
lookup node can be serialized
Lookup node is now working.
 Save behaviors to module "behaviors" (overrides or assets dir)
 Assigning behaviors to minions.
added remove button in editor.
Merge pull request #871 from synopia/behavior

Behavior integration improvements
Fixed gathering of sub types from active modules (was not checking the full hierarchy of subtypes)
Merge branch 'develop' of git@github.com:MovingBlocks/Terasology.git into develop

Conflicts:
	engine/src/main/java/org/terasology/engine/bootstrap/EntitySystemBuilder.java
Switched NodesClassLibrary over to using the new findAllSubclassesOf method.
Merge pull request #861 from mkienenb/headless-assets

Create Headless and Base graphic-related assets
Implemented NUI-based pause menu and death screen.
Merge branch 'develop' of git@github.com:MovingBlocks/Terasology.git into develop
Fixed unit tests.