Demo complete

Made more of a usable demo version.

- Restricted player movement to appropriate areas.
- Added raft, and violet colour.
- Fixed softlock on top of hill, and at edge of bridge.
- Added bridge functionality. (You can only walk across the bridge if you can see it.)
- Added congratulations text after completing all the objectives that currently exist. (Obtaining three colours: red, green, and violet.)
- Made the character face the correct direction (walks backward when moving backward through time, forward otherwise).
- Added an indicator to show when you're in a state where you can interact with an object.