Auto crawl

Auto crawl related :
* Added an "auto crawl" option in the options page.
* In the background page add tab action listeners to send crawl requests if auto crawl is on.

Other Changes :
* Make e2e test hopefully work in travis
* Create an options service with code from options controller 
   * the idea being that any page querying for options shouldn't hit local storage except during the initiation.
   * Also added watchers to make changes to options propagate immediately to all pages through the localstorage
* Fix the url that shows in crawl page in the presence of multiple
windows
* Added a link to options page in the browser action page