use new apipkg __onfirstaccess__ feature to initialize the py.test namespace with the default plugins. This, besides other good implications, means that you can now type: pydoc py.test or help(py.test)
--HG--
branch : trunk
* separate all tests from plugins
* simplify implicit inclusion of plugins under test
* have test_initpkg perform direct checks instead of yielding tests
* fix example tests for 3k
--HG--
branch : trunk