Fix some typos in the ttx usage instructions
Fix some typos in the ttx usage instructions

Patch-by: Paul Flo Williams <paul@frixxon.co.uk>
Fixes: https://bugzilla.redhat.com/694387
Fixes: http://sf.net/support/tracker.php?aid=3279073

git-svn-id: 05b73559aeb8bace4cf49b5ea964569f1305eff8@590 4cde692c-a291-49d1-8350-778aa11640f8

fonttools/fonttools,googlefonts/fonttools