converting the old buffer for PyArgs_ParseTuple with *s

fix #10340: properly handle EINVAL on OSX and also avoid to call handle_connect() in case of a disconnetected socket which is not meant to connect.

Patch by Guilherme Polo.

allocating path buffers on the heap instead of the stack.

(Patch by Dionysios Kalofonos)

 explain json.dumps for non-string keys in dicts. closes issue6566. Patch contributed Kirubakaran Athmanathan