Bug 898352 - Implement homescreen rocket bar and opensearch.

This pull request implements "rocketbar", a search bar on the gaia homepage. The rocketbar will currently search:
* Apps on the device
* Web results from Google, Wikipedia
* Apps from the marketplace
* Web results from Everything.me

Everything.me and Marketplace results currently leverage a proxy on my server to handle augmentation of their search APIs. This is only temporary as the final result will be using a standardized opensearch result directly from their servers.