New operations for obtaining elements and the size of arrays, maps, etc.
New operations linked to operator factory
Test updated
Comments addressed
GameLayers => GameView
Merge pull request #536 from jtorrente/gamelayer-to-gameview

GameLayers => GameView
Back and forward icons changed
Updated icon if interactive zone
Merge pull request #537 from anserran/backnexticons

Back and forward icons were too similar to undo/redo
Merge pull request #530 from jtorrente/get&size_operators

Get & size operators for collections