proper unicode conversion of the request in server post method
fixed pyton3 TypeError: 'dict_keys' object does not support indexing (server)
removed unicode literals and fixed print syntax for python3 (tests)
fixed issue 139: better support for extension (wsdl parsing)
added test for issue 139 (extensions in wsdl parsing)
commented process_element wsdl helper
added test for issue 141 (ref to element in wsdl parsing)
fixed issue 141: references to elements in wsdl parsing (tentative)
avoid recursive errors while postprocessing wsdl elements
fixed some recursion issues (tentative patch)
updated issues tests (url wsdl, assertions/exceptions, etc.)
updated package version