Updated feature detection and description to work more robustly.

Mainly, replaced Brisk detector with Fast detector and removed gaussians.
New use-case specification (not implementation) done for refresh. Fails at the expected spot.
Leaving refresh until speed becomes a problem.
adjusted feature parameters
bugfix: allowed scale was doing area / 2 (ok) and area * 2 (way too big).
changed to area +/- 50%
manual test