Add a copy of Open Sans' license to comply with it

The font can be found at this URL:

  http://www.google.com/fonts/specimen/Open+Sans
First cut: add new data blobs
Fix up some stuff
Too spammy
Update data format number
Fix logging, update docs
Add missing Australis 48x48 icon (fix #575)

This was generated from `assets/logo-only/lightbeam_logo-only_charcoal.svg`
using inkscape.
Fix timestamp parsing
Really fix version numbers
Merge pull request #576 from fmarier/issue575

Add missing Australis 48x48 icon (fix #575)
Merge pull request #565 from fmarier/font_license

Add a copy of Open Sans' license to comply with it
Merge pull request #574 from mozilla/data

New data format (fix #515)
First cut at upgrade notification
Rev version number (this doesn't matter until we submit to AMO but will not trigger the upgrade experience otherwise
Add warning for data loss
Add a Makefile to make it easy to run the linter
Merge pull request #570 from fmarier/makefile

Add a Makefile to make it easy to run the linter
Switch all feedback requests to lightbeam-feedback, fix broken link, fix indent
Merge pull request #578 from mozilla/update

First cut at upgrade notification (fixes #520)
Keep contribute data pref from v 1.0.9