Updates to tutorial based on Despo's feedback; link to getting started guide from the index.
Fix Go Mockingbird link
Minor tweaks

Grammar, consistency, whitespace
Flesh out getting and setting with the same method
Flesh out event listeners intro
Merge pull request #138 from jamesjoshuahill/js-lesson-3-amends

Flesh out 'Introduction to jQuery'
Merge pull request #137 from creature/gh-pages

Updated getting started guide, and expose that in the tutorials
Merge pull request #135 from jamesjoshuahill/fix-js-tutorial-8-typo

Fix Go Mockingbird link