Refactoring out Core Module code

Most refactoring complete.  Need to fix up the tests and benchmark code.
#1 #2 #7
Move over benchmark code; fix biomeProvider instantiation

benmarks not functional yet
Water is pretty again
Add API safeness to externally registered chunk/world generators
Move blocks to core

A couple things remain: core:grass rendering, water and lava and ice
still in engine
Added menu entry for "Drop Item" and "Hide HUD"

Fixes #666 - lol
Merge pull request #752 from msteiger/mbts_dev

Added menu entry for "Drop Item" and "Hide HUD"
Save window position on exit (centered by default)

Fixes #194
Add mockito as a test dependency for modules and @API to FastRandom
Merge branch 'develop' of github.com:MovingBlocks/Terasology into mbts_dev
Merge pull request #753 from msteiger/mbts_dev

Save window position on exit (centered by default)
Fix incorrect URI to water and lava
Merge branch 'develop' of github.com:MovingBlocks/Terasology into mbts_dev
Updated .gitignore to deal with eclipse project files
Stop root project from being an (empty) eclipse project

Eclipse does not support sub-projects
Root exception dialog displays nested exception messages
Move water, lava, and ice to Core

This leaves just air in the engine
Extract the initial player inventory to Core

close #4
Tweak comment for #754
Added UIElement interface covering both widgets and screens.
Added tracking of the UIElement with focus, and onGainFocus/onLoseFocus events.
Fixed some fencepost errors.
Added dropdown widget.
Added support for rendering on top.