PIVOT-922: Correc the last renderer that isn't correctly calling "toString"
in the "render" method.  This change also correctly ignores pure Image data
which shouldn't have text.

This is a merge of revision 1523776 from trunk to branches/2.0.x.


git-svn-id: https://svn.apache.org/repos/asf/pivot/branches/2.0.x@1523778 13f79535-47bb-0310-9956-ffa450edef68