Add Python 3.4 build options
Python 3 compat: Improve various bits

This includes changes to WSGI, websocket, bytes/str/unicode handling,
SSL, backdoor, greenio and tests.

Some comments and conditionals (PY2/PY3) were added for clarity

GH issues:

Closes #106
Closes #111
Closes #118
Closes #141

Incidentally should also close #135 (reopen if didn't)

cc #6