New UI for the changes to talk rating

This new UI allows users to rate a talk on two criteria:

- The quality of the speaker (the presentation)
- The quality of the content

The new UI:

- Shows BC rating if no split rating has happened
- When rating, each "star" has a descriptor to promote consistency across users voting choices (rather than arbitrarily choosing what the numbers mean to them)
- Displays Overall/Content/Presentation ratings for the talk
- Hides comment rating breakdown until hover
- Hides speakers ratings completely
- Highlights speakers as speakers
Add Bootstrap 3.1.1
Add FontAwesome 4.1.0
Update jQuery to 2.1.1
Switch to using Bootstrap

- Now actually responsive!
- Adds sidebar
  - Login, takes you back to the same page
  - Splits to have event info on top of page, login below page
  - Combell logo disappears on mobile, as it's directly above the footer which also contains it
- Added a link to github in the footer (left)
- Nicer pager
- Clearer (actionable) "I will be attending"/"I attended" text+buttons
- Short URLs now have a "Copy to Clipboard" UI
  - uses flash but:
  - is hidden on mobile/tablet
  - will highlight the text in the input when focused, or clicked without flash
- Comments have a new interface
  - Supports gravatar
  - Comment shown above author/date/via
  - via is hidden on mobile
  - When ratings are shown they are also responsive:
    - Horizontal/on-top for desktop
    - Vertical/left for small/tablet
    - Vertical/on-top for mobile
- Twig will check for local images before linking to the old joind.in site