Command Line Interface for pxarcore

This adds two main new features to the pxar software package:

1) A Cython interface to allow access to all pxarcore API functions in Python scripts
* Full wrapping of the pxarcore API

2) A first implementation fo the above feature: a command line interface for pxarcore featuring
* config file reading/parsing for automated DTB startup (compatible with regular pxar config file format)
* tab completion for commands
* tab completion for parameters (DAC names etc.)
* ability to load scripts (as in psi46test) with a list of CLI commands
* ability to write Python tools using the pxarcore abilities
* Nice-printing of events & pixel hits via Python's `print`