For #377 - merging new mobile section with fixes, linkifying URLs, correcting image paths
Merge branch 'gh-pages' of http://github.com/addyosmani/backbone-fundamentals into gh-pages

* 'gh-pages' of http://github.com/addyosmani/backbone-fundamentals:
  Fixes to the new Event Aggregator/Mediator sections
  More cleanup.
  Internals chapter: tweaked first paragraph of Events section.
  More minor updates to recently changed sections.
  Extensions: minor corrections, including removing redudantcy in Thorax Hello World section.
  Fundamentals: minor punctuation and typo fixes