Added missing preposition to text trim.
Back-propagated changes to messages.js, including http->https.

R=neil.fraser@gmail.com

Review URL: https://codereview.appspot.com/44420045

git-svn-id: http://blockly.googlecode.com/svn/trunk@1571 c400ca83-b69d-9dd7-9705-49c6b8615e23