Implemented workaround for use swift mappings for core data.
Added toolbar

Added toolbar with items for modes: for move items and edit
backgrounds. added images for icons
Impelled basic functionality for draw background

* Added test image for background sprites
* Separate units and background sprites into different nodes.
* Implemented ability change edit mode: units / background
Implemented add new and change background nodes in tracking loop
Fixed Z ordering for background nodes
Implemented save moving items to model

Implemented get delegate event in editors viewcontroller from units
editor node.
Implemented scroll canvas

Implemented scroll units and background nodes. Configured responder
chain.
Edit units list moved to separated controller.

* Added ViewController for edits units;
* Added xib for UI;
Fixed functionality for add/remove units
Implement change edit panel on change edit mode.
Merge branch 'CustomizeBackground' into CustomizeBackgorund
Merge branch 'CustomizeBackgorund' into LevelsEditor