Update JS tutorial 1

Included one unnecessary semicolon, which a vigilant student caught, and a missing parameter to a function
Merge pull request #127 from creature/gh-pages

Expand the HTML 1 tutorial based on confused areas last night.
Minor fixes to lesson 3

-h2 → h1
-b → strong
Merge pull request #128 from charlieegan3/gh-pages

Minor fixes to lesson 3
Merge pull request #125 from passy/patch-3

Update JS tutorial 1
minor corrections to the JS Lesson 3 tutorial
Merge pull request #130 from mrjamesriley/gh-pages

minor corrections to the JS Lesson 3 tutorial
JS Lesson 4 update

The GitHub API changed and removed Gravatar URLs completely:
https://developer.github.com/changes/2014-09-05-removing-gravatar-id/

My students also had some trouble following the instructions given the very
loose structure. I added a bit more explanation around JSON and guidance for
implementing the XHR call method.

A student also mentioned that is what hard to follow because they didn't know
what the end goal of the tutorial is, so I added a link to the finished example
to the top.
Merge pull request #132 from passy/lesson4-update

JS Lesson 4 update
Rework HTML tutorial 6.

This started as a simple grammar fix, but has ended up as a major
rewrite. As well as fixing up the grammar and typos, I've tried to make
this clearer based on the areas that I've seen students struggle with,
as well as simplifying the language.