Debug rendering

[hexus]

Implement the rendering of debug geometry for:

• Tile polygons
• Tile face properties
• Collision vectors (a little more tricky)
• Broad-phase tiles

The crossed out tasks will be saved for a later version.

[hexus]

Cool. ( ͡° ͜ʖ ͡°)

[hexus]

While it's a touch slow with a lot of colliding tiles in view, it'll do for now.

The slow down is from rendering the normal debug shapes and the slopes debug shapes.

Disabling either by nulling their fill/stroke styles is a workaround.