Make it easier to detect errors in tests. https://code.google.com/p/closure-library/issues/detail?id=559

Hello @dpup, 

Please review the following commits I made in branch 'nick-deferred'.

d4be021ea0b1d1c8d6ec3da99a000915c927fe3e (2013-07-17 13:43:38 -0400)
fix deferreds


R=@dpup