Add pearyd

Add a pearyd executable that implements a peary-as-a-daemon and an example python client. This is a more generic version of the ATLASPixServer already available in the code base is intended to replace it at some point.

pearyd is implemented as a TCP/IP server with a minimal Request/Reply protocol to call device functions and return the result. With the new dispatcher this should simplify calling device-specific functionality without having to modify other parts of the code.

Replaces the ExampleDevice with ExampleCaribouDevice implemented without a hardware abstraction layer to allow testing on a regular machine w/o the caribou hardware.