Use tripleclick to zoom to base pair level and out.

About tripleclick event:
http://benalman.com/news/2010/03/jquery-special-events/

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Remove gear menu. Make Scroll to next / prev edge independent buttons.

Additionally, move scrollToNextEdge and scrollToPreviousEdge functions from
Browser.js to GenomeView.js.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>