Add search functions to sort results by hit count.
Add mocha tests for search functions.
Add namespace for searching functions.

Wrap in a `searching` namespace for global sanity. In in node (for mocha
tests), pretend we're in an AMD module.
Add unit tests for search ranking.
Improve search matching algorithm.
Wrap shared search code in an anaonymous block.
Merge branch 'master' of https://github.com/gillibrand/launchbar-pinboard