Asyncio

Working asyncio and aiohttp implementation, replacing the ``requests`` library (for talking to bitcoind's multiple RPC threads asynchronously).  You should use python 3.4.1 or newer due to this bug: http://bugs.python.org/issue20275 which results in spammy logging with ``--verbose``.  aiohttp is relatively new and you should install it from git for now. https://github.com/KeepSafe/aiohttp

It may be possible to get this to work under python 3.3 as well, but asyncio must be installed as an external package.  (It comes with python 3.4).