Make memmon and nofast loading query string options

Disable memory monitoring by default. Re-enable with ?memmon in url.

Use ?nofast in url to force non-TypedArray version even in TypedArray browser.
Missing closePath in draw_poly
Add NARROW_BORDERS build option, to allow frontend to supply padding around gameboard.

Includes fixes for games that use BORDER, but were assuming it was always TILESIZE/2 in some places:
- Filling (game size, text)
- Range (game size)
- Undead (monster count display)

Defines and uses BORDER in games that were hard-coding padding:
- Blackbox
- Unruly
Build with NARROW_BORDERS; supply gameboard padding in responsive CSS.

(Also stop building with SMALL_SCREEN -- it now only serves to omit some presets since NARROW_BORDERS is defined.)