Background, changed most tiles, added a few bars

Added background (upper smoky city type and bottom dirt-rock type), changed the look of most tiles. Added tile for oil, for robot to regain fuel at fuel reservoir. Quick bar works for placing dirt and stone on the map (other things will be added later; like dynamite etc.).

Added a a few bars:
- Energy bar (used for crafting and researching)
- Oil bar (for filling fuel reservoir)
- Research bar (for researching new technologies)
- Shield bar (for reducing incoming damage from enemies)
- Health bar (already existed; robot health)
- Fuel bar (already existed; robot fuel - for jet, digging)