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
Added cut to scene elements
Small changes after rebase
Refactor cut to copy(true) to be more consistent
Renamed addFromImage -> generateSceneElementFromImage
Improvements in deletescenetest
Added i18n strings for cut,copy,paste
Added listeners mechanisms to clipboard, so paste action listen and cans set if it's enabled