Input <- Startup, LayerList, TopMenuModule: Could be resolved by using custom events

Startup <- ColorModule, ToolManager, LayerList, EditorState, Layer(++)

EditorState <- LayerList, File, Startup(documentCreated): maybe documentCreated should stay in EditorState (that would fix the
				circular dependency with Startup), for the other dependencies it'd probably be nice for them to listen to a custom events

Color <- NONE

ColorModule <- File

File <- Startup, but only because Startup sets certain variables in File (pixelGrid, checkerboard and the other global layers)