PIVOT-924: Provide a standard mechanism in BXMLSerializer to report exceptions
so that a particular application can subclass and report exceptions in a different
way than writing to System.err.

This is a merge of revision 1536829 from trunk to branches/2.0.x.


git-svn-id: https://svn.apache.org/repos/asf/pivot/branches/2.0.x@1536841 13f79535-47bb-0310-9956-ffa450edef68