Ensure that EntityProxy instances returned from Collections returned from an editable EntityProxy are editable.
Patch by: bobv
Review by: rjrjr
Found by: pjulien

Review at http://gwt-code-reviews.appspot.com/976801


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@9024 8db76d5a-ed1c-0410-87a9-c151d255dfc7