Rewrite the UI to render entirely into a Canvas

[electronoora]

Rendering the player UI using a complex DOM and requiring pixel-perfect positioning causes various performance and compatibility issues. Using a pre-rendered fontmap image and rendering the UI fully into a Canvas first, and then to the screen would likely improve performance, and simplify the code.

Clickable UI elements would need a mechanism for registering event callbacks to provide hover/click functionality.

As an additional bonus, this would also rewrite out the dependency to jQuery.