[wip/py-poco] Updated to pypoco-1.4

Changes since pypoco-1.3:
- fixed a bad issue when using 2 instances of pypoco in the same application.
  Because of global variables, sockets would be reused, which is not the
  expected behaviour in general.
- fixed a bug when force closing sockets

Changes since pypoco-1.2:
- Fixed a bad deadlock when sending asynchronous requests. Done by
  rewriting the network code to use two sockets, one for control, one
  for asynchronous answers.
- Fixed the ABORT logic. Request can now be correctly aborted
- Changed the behaviour of PocoProxy.request() to return a PocoRequest
  object that allows easy abortion of asynchronous requests.
- Added a global pypoco.close() method that closes all open connections
- Added a pypoco specific logger (called 'pypoco')
- Replaced tabs indentation by spaces