Added configuration_settings.json.

This is a first jab at a settings file. I'm giving it a very restrictive
name to suggest that other types of settings can (and should) exist in
a similar file.
Started grapevine.py, which defines a communication object.

This is untested, not fully featured, and incomplete.
Added publisher and subscriber contexts.

Again, this isn't tested/working (class calls).
Communicator object now works.

This includes basic functionality. I still need to do a proof read and
add comments before sending it through a review process however.
Release candidate 1 for grapevine.py.

This introduces a communication protocol for robosub modules.
Added a demo beaglebone script.

This has more functionality than we really need, and it assumes more
pins than we plan to demo with.
Created demo code for the beaglebone.