Allow Editor framework to handle primitive types.
Issue 5864.
Patch by: bobv
Review by: rjrjr

Review at http://gwt-code-reviews.appspot.com/1312802


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@9607 8db76d5a-ed1c-0410-87a9-c151d255dfc7