Priority based queue used in ChunkMeshUpdateManager.
Improving handling of shutdown (highest priority).
Make it possible to attack and interact with characters.

This patch makes it possible to attack the deers in the WildAnimals module.
Update module lineup and credits
Make the BehavioSystem run on Authority only.

Reasoning: Locations and a few othere data get already transfered
from server to client. Having servers and clients both calculate
unit movement, expecially in a not deterministic way would be a bad idea.
Replicate the currently selected animation to the client.

Reasoning: Only the server runs the behavior trees to determine the unit
behavior. In order for the client to play the correct animation it needs
to be transfered from the server.
Merge PRs #1439 & #1440 by @flo - behavior updates and attackable creatures/players
Add WildAnimals to lineup
Add 2D boolean facets
Add comments to BooleanFieldFacet2D
Merge PR #1442 by @msteiger - 2D boolean facets
Fix for fetching the Index lib - lives in the Terasology org
Add MarkovChains to the lineup
Make the passing of the camera position to the ChunkMeshUpdateManager robust and clear.
Provide generated chunk regions
Merge pull request #1447 from msteiger/chunk_provider

Provide relevant regions to modules
Add engine module as dependency for all modules
Merge pull request #1452 from msteiger/engine_mod_dep

Add engine module as dependency for all modules
Fix 2 typos.
Reordered methods in the WorldRendererLwjgl class. No functional changes. Related methods are now near each other. Accessors (getter, setter, etc) are now close together at the end of the file. This commit paves the way to split the class into two, one for rendering, the other for keeping renderable meshes up to date.