Some fixes for the Todos app chapter

Fixed some typos and inconsistencies.
Merge pull request #255 from jdreesen/patch-1

Some fixes for the Todos app chapter
Adding a revised introduction.
Further tweaks.
Fix typo. Closes #241.
Fixed some typos and spacing.
Merge pull request #258 from ugisozols/fix_typo

Fix typo. Closes #241.
Merge pull request #257 from ugisozols/fixes

Fixed some typos and spacing.
Merge branch 'gh-pages' of github.com:addyosmani/backbone-fundamentals into gh-pages
require JS and backbone examples
add RJS bit