preparing 2.5.0 release announcement
regen docs and bump version to 2.5.0
Updated plugins_index.txt with latest plugins
fix expicit assert messages for Python2.6: it turns out python2.6
instantiates the AssertionError differently for tuples.  Test
and fix to neutralize it.
remove unusued import
don't declare py25 as supported anymore.
remove py25 from automated testing
fix typo
Added tag 2.5.0 for changeset a064ad64d167
some doc fixes