Avatar movement draws lines on map

TODO:
- Shift canvas with map OR insert canvas into map (ideal)
- Figure out how to draw for multiple players
canvas el in map template, SnowDrawer model
SnowDrawer => Trailblazer. Semi-transparent non-overlapping paths
removing public assets. thicker snow trail
cleanup snow trail on game loop
cleanup
Merge pull request #2 from cremalab/snow-draw

Snow Trails