Merge pull request #933 from MarcinSc/develop

Adding hook for rendering inventory cell overlays for items.
Remove the develop branch tweak from fetchFacade as the master branch for AWT is back on top again (and will be default for fetched facades)
Added @LayoutConfig annotation to mark which UIWidget fields can be configured in layout assets (for clarity and safety).
Added removeHUDElement() methods to HUDScreenLayer
Merge branch 'develop' of git@github.com:MovingBlocks/Terasology.git into develop
Add @API to BlockDefinition so that modules can define block families
Merge pull request #935 from Josharias/EnableFamilyFactory

Add @API to BlockDefinition so that modules can define block families
Add relative side convenience method
Merge pull request #936 from Josharias/AddRelativeSide

Add relative side convenience method
Remove lwjgl dependency from Performance Monitor
Move headless classes into headless subsystem
Merge pull request #939 from mkienenb/PR-PerformanceMonitor-lwgjl-dep

Remove lwjgl dependency from Performance Monitor
Merge pull request #940 from mkienenb/PR-consolidate-headless-code

Move headless classes into headless subsystem
Added new component system lifecycle methods. This probably breaks every module - I suggest switching to inherting BaseComponentSystem to both avoid having a number of empty methods and protect against future change. Hopefully there won't be much of that.
Added AutoCreate component and system, for prefabs that should be automatically instantiated.
Merge branch 'develop' of git@github.com:MovingBlocks/Terasology.git into develop