Fixed a few typos.

This is a dupe of #1598 (1 commit into chriseppstein:stable from KatieK2:patch-1) which I guess somehow got on to the wrong branch, which was having build problems. Hopefully this is the right place for it. Use this one - really for realz.
Merge pull request #1601 from KatieK2/patch-2

Fixed a few typos.