0.1.6 (Wimbledon Park) released

0.1.6 (Wimbledon Park) is something of an interim release, as it includes a lot of internal changes and new features, but several aspects of it are still very unpolished so I'm reluctant to go for a 0.2 release yet. Key changes in this release are:

• Completely overhauled the camera system again. This update allows for significantly more camera flexibility, and smoother and more usable controls. As before, hold right mouse button to rotate the camera, mouse wheel zooms in and out.
• Initial version of the level editor is included and functional, albeit in a rough state with no keyboard hints: pgup/pgdn changes floor, wasd moves the camera focus, z/x rotates the cursor, right mouse button rotates the camera around, left mouse button places objects when in placement mode and selects objects in selection mode. The "Test" button doesn't currently work!
  
• Integrated an onscreen performance monitor: press F3 toggles display, F4 changes the display mode.
• Replaced the way that level saving and loading works to allow the level editor to operate outside the Unity editor.
• Proximity mines added - they can be pushed, but otherwise are invulnerable. If something moves onto an adjacent square, the mine will explode destroying itself, anything in adjacent squares, and potentially the floor under the mine.
• A couple of new levels added, these were created in the in-game editor! 
• Music subsystem added to the game. The current music is temporary Kevin MacLeod music to test the music loading and crossfading system works, at some point it'll be replaced.