Cloud nine ideation: limit backing track searches

The idea: Random return of backing tracks, limit to max no. of returns.

This would be somehow part of the backing track search screen.
The ability to limit its returns. Ex: A cool little 'return 2
folk drum tracks without keys' would be neat.

In terms of coding, it would return the a random selection of
tracks that met the search.

Possibly a restricted date range could be added, but that
would make jist of this post no fun, that being
'i want wikiloops to return 2 random drum tracks
from genre (your selection) that don't include keys'.

---