Fix for issue #529.

* replaced precondition with if-statement in class ChunkMeshInfo.
Merge branch 'develop' into monitoring
Merge branch 'develop' of https://github.com/MovingBlocks/Terasology into monitoring
Refactor gitignore
Replace tab with spaces
Change comments and idea module dirs
Simplify world listing and change to dates in ISO 8601 format. WOO ISO 8601 !
Merge pull request #535 from mkalb/gitGradle

Refactor gitignore and build.gradle
Rename a Dev class to avoid a naming conflict in IntelliJ. This previewer hasn't actually worked for who knows how long anyway (wonder how long ago we deleted "Biomes.png" ..) - but don't want to start a deletion spree or anything
Miniscule fix for missing space in single player ui.
Fix for issue #532.
Merge #530 by @mbrotz to fix #529
Added DoubleClickListener to module dialog.
 Double clicking toggles mod selection.
fixed core mod toggle bug.