Allow Block Factory to create blocks starting with the letter 'D'.  Fix issue 148 (crash when clicking into a textinput field in a toolbar with no categories).  Fix issue 158 (crash on load due to bad editable check).

R=spertus@google.com

Review URL: https://codereview.appspot.com/12391043

git-svn-id: http://blockly.googlecode.com/svn/trunk@1177 c400ca83-b69d-9dd7-9705-49c6b8615e23