Unit Controls

[sethjwhitaker]

Implement controls for selecting and moving units. Should use drag to select and click to move selected units.

• [x] Create translucent box when drag starts
• [x] When left mouse goes up, check for any selectable gameObjects whose screen coordinates are within the box
• [x] If clicking without dragging, check for any selected units, and send them to clicked hexagon
• [x] Give a hexagon 10 slots for units, and make them fill up one at a time
• [x] If a hexagon is full, any selected units should go to adjacent hexagons instead.