Make noun and antecedent agree.

"students … their"
Edit parenthetical.
Edit for grammar and spelling.
Edit "Rules separations" so we don't contradict ourselves.

See "Capitalization" section.
Remove empty header.

One of the things the validator complains about.
Add missing recommended header.

I thought it was just a stray header earlier. Thanks for catching this, Mike.
Merge pull request #1 from danielmai/gh-pages

Edit for grammar, spelling, and style guide agreement.