LibGDX API changes, see https://github.com/libgdx/libgdx/pull/2490
Merge pull request #908 from RotaruDan/apiChanges

LibGDX API changes, see https://github.com/libgdx/libgdx/pull/2490
Q isGroup
selection contains
fix in model
Fix in mokap views
Number 2 as second pointer in the middle of the screen
Fixes in Entity group
Fixes in group creation actions
Fix in remove selection
Some methods for engine utils, dealing with groups and transformations
Fixes in back
Visible listener refactored
Fixes in group/ungroup
Minor fixes