Format
libgdx removed GLCommon
While we fix #107, which I think it's becoming rather important, I've added a "FIELD_NAME" constant in several actions where the action name matches the name of the field they are changing. Hopefully this will trim down confussion:

In Actions, the NAME should be referenced from the "views" package.

 the FIELD_NAME should be referenced within the actions package only (e.g. DeleteScene references InitialScene.FIELD_NAME because it may need to change the initial scene of the game).
This is needed for delete scene to work.

Surprisingly, this was missing! I guess in a previous PR I missed to commit this or I made a mistake while resolving conflicts...
Refactoring of FieldCommands. Now, the name of the fields are identified using an enum instead of strings
Moving the field names enum to the model
Renaming FieldNameForActions > FieldNames
Merge pull request #119 from jtorrente/editor-renamescene

A couple of changes related to scene actions
Format
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