Post-jam update

This update addresses most of the feedback which I got during voting period.

• Less slippery movement.
• Redrew selection circle (to not confuse with the term time bubble) and items are highlighted under cursor when reachable.
• Doc leaves a trail of footprints now! This makes it easier to see, where you were when rewinding time. Originally there wasn't much feedback on rewinding mechanic, leaving some not to understand how it works.
• Objects touching the time bubble are shaded differently, making it easier to understand how it works.