python 2.x bug fixes: changed super syntax, etc
adding gui server to examples
fixed python 2.x bug: xpub subscription unicode parsing error
adding warning for zmq version < 3, notifications won't work due to hidden subscription messages with xpub
New example with two servers
Updated gitignore
Refactored code, some tests are not working.
Refactored code, all test passing

- Renamed logger to LOGGER
- Rewrote launcher to serve in process