Fixes Issue #733 Replaces the toString implementation in the XML library to use native XMLSerializers instead of the DIY job we currently have. I also had to change XMLTest quite a bit because it leaned very heavily on the broken implementation of toString in assertions. Review by: jgw git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@2650 8db76d5a-ed1c-0410-87a9-c151d255dfc7