Added DeleteProject action.
Adapted GalleryGrid to support deletions.
Implemented delete functionality for galleries.
Fixed severall deletion bugs, improved galleries deleting functionality.
Small bug fix: changed Scene to EditorScene.
Added DeleteProjectTest
Merge pull request #165 from RotaruDan/DeleteFromGalleries

Delete projects/scenes from galleries.
Fixes #173
Added getKeyboardFocus to views
Added clipboard
Added cut, copy and paste actions
Added copy paste of scenes
Avoid pasting when clipboard is empty
Refactor ScenePasteListener to use AddScene action
Added better handling for setting keyboard focus owner
Added sceneleemnt copy paste
Docs for clipboard
Adde cut to scenes. Small bug fix in delete scene, along with a new test for it
Adde cut to scenes. Small bug fix in delete scene, along with a new test for it
Refactor in SelectedOverlay