Refactors event infrastructure, to simplify the firing mechanism and allow users to cherry-pick the non-Dom events. Patch by: jgw Review by: ecc, rjrjr git-svn-id: https://google-web-toolkit.googlecode.com/svn/releases/1.6@4494 8db76d5a-ed1c-0410-87a9-c151d255dfc7