PEP8 whitespace
PyPy 2.3 compatibility fix

In PyPy 2.3 socket.socket has no _sock property which causes eventlet
failures.
https://github.com/eventlet/eventlet/pull/97
greenio, tpool: python3 compatibility

Also:
- PEP-8
- check both EAGAIN/EWOULDBLOCK
- use system implementation of GreenPipe.readinto()