Changed GraphHost protocol and added documentation.

The client can now request a list of datasets. The client can
request that the server stop sending data for a particular dataset.
The dataset name length has been shortened to 15 characters from
the original 16 character length. Documentation on the API and
protocol was added.
Added documentation for GraphHost.
Added an end-of-sequence indicator to the dataset response structure, and updated documentation accordingly.
Added include guards to Settings.hpp ; added PID constant loading and enabled PID loops for MecanumDrive class ; added PID constants to RobotSettings.txt
Merging new LiveGrapher host code into working branch