Added a way for EntityProxy to have a stable equality using getStableId(). The getStableId() is stable across creates and updates on the client. Patch by: amitmanjhi Suggested by: robertvawter Review by: rjrjr (tbr) git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@8733 8db76d5a-ed1c-0410-87a9-c151d255dfc7