Changed low-quality to only be during scroll events

Scrolling is the only time where we really care about the performance of
draws. Therefore, after no scrolls for 1000ms, we'll re-enable high
quality drawing.
Added menu line
Tweaked alpha effect to support inwards

Using a negative delta will now flip the points & offsetPoints (and
polygons) to apply the fog effect inwards.
Cleanup of fog update call to sync to main