Deleting some mostly unused code
Remove a few unused imports
Breaking API changes and large internal refactor

The public API for clients and services has changed. Service is now
TCPService and Client is now TCPClient, which goes along with the
existing UDPService and UDPClient classes.

The main internal refactor is that all of the TCP and UDP transport
code is now in the diesel.transports package. diesel.core is much
slimmer and some circular dependencies that were worked around with
lazy imports are now resolved.

All of the protocols should be in line with these changes. Not all
of the examples are yet. All unit and integration tests pass.
Add transports package to setup.py
Add a basic TCP transport test

Creates a simple service and client and has them communicate a bit.
Use constants
Integration test for UDP

Also fixes a few bugs. One was an old bug that wouldn't allow you to
bind to port 0 for a UDP service. The others were new and related to the
transport refactor.
Only accept valid UDPService handler callables

Previously you could get your app in a weird semi-frozen state by
passing a bad handler callable.
UDPContext: Remove unused parent argument
Fix up some broken examples
Merge pull request #96 from dowski/transport-refactor

Factor Transports Into First Class Module, Remove Defunct Code