Extract CLI for Brick-flashing

This pull request contains a rudimentary command-line interface for the firmware-flashing of bricks. It is implemented in a small python-script.

A major design-goal was that brickv and CLI can use the same module (no code duplication), for this reason I did not completely remove the progress-code from the SAMBA-class.
This also allows to indicate progress in the CLI-script.

As of now I did not test this code. I will do this when I got all dependencies running. However you might still want to take a look at the current state of the implementation.