Pure python launcher now equivalent to run.sh.

Just needs --config parameter to accept a configuration file on startup and I'll submit this
as a pull request to develop branch. pep8 compliant, all python tests pass.

Will also need to merge latest changes after this point, to make sure this will be easy to merge
with latest changes on master.

 - Supports development mode, launchers multiple instances, makes sure every instance has db setup. refactors.
 - configure.sh: make sure to use env/bin python tools, small refactor.
 - requirements.txt: fixed pystun requirement
 - openbazaar (posix CLI launcher) makes sure openssl library is in DYLD_LIBRARY_PATH if running on macosx.

 Fixes on transport.py:
 - commented out inet_pton calls. inet_pton wasn't actually
 doing anything except raise exceptions. in the event that
 inet_pton would actually work, its output was not being used
 to obtain the ip in raw network format anyways.
 - now when we shutdown transport, we make sure the zmq event
 stream is closed properly.
 - in case the market_id is different after we load the settings
 we make sure the OpenbazaarContext object knows is updated.
 - ipv4.icanhazip.com fix on periodic callback updater (fixed merged from master branch)