Refresh the "Find a trace" section of the web ui

This will start the migration to Bootstrap3 and Flight. JS package management is
handled with Bower, but packages are picked apart by hand and committed directly
to the repo so as to not require a full suite of JS tools if someone wants to
simply build and run the UI.

Author: @sprsquish
Fixes #347
URL: https://github.com/twitter/zipkin/pull/347