Skin changes
Added ColorPickerPane improvements
Now the TextEditor and BrushStrokesPicker panes have variable number of rows of colors
reference.json component.
Adds REFERENCE_PREFIX to GameAssets.
Adds ReferenceComponent and ReferenceProcessor.
GameStructure ~> ModelStructure. Adds library structure to ModelStructure and default library folder.
Adds Controller to ProjectUtils. Implroves Q and WidgetBuilder statics initialization.
Adds CopyToLibraryEntityResources worker.
Add RepoElementReference action.
RepoTile and SearchGallery changes to import downloaded elements to the library.
Removes uneeded attributes from GameAssets.
Adds LibraryManager to the Controller.
CopyToLibraryEntityResources ~> CopyToLibraryWorker.
Merge pull request #923 from RotaruDan/library

Library
New resources
Removed completion percentage from bgtask
Action on click listener now can execute more than one action
setTitle/getTitle methods for Q
Improvments to WidgetBuilder