Documentation update

This is rather small update but it brings to light important feature that was not documented before - getting short timezone abbreviations (I almost abandoned using `timezone-js` on one of my projects because I didn't knew that it was there).

There are 3 commits - all related to the documentation. One documents abbreviation feature, second contains minor formatting fixes, third adds myself to contributor's list (not sure what is your policy on that, hope that's ok).