Support for the Extron Crosspoint 450 Plus

[formlesstree4]

I had a conversation the other day about expanding the system to support the Extron Crosspoint 450 Plus. This system is a bit more complex than a System 8 or 10 which was the original thing I wanted this library to support. However, the good news here is that it is also less complicated in other ways.

I am starting to take a look at the programming API and I think I will be able to devise a new interface to implement and even begin providing cross-support between the two systems and sort of develop this unified API between the Crosspoint 450 Plus and System 8/10.

As for a UI, the UI will have to be something entirely different in order to support the functionality that exists on the Crosspoint 450 Plus. So that will be something entirely from scratch.

This issue is being opened now as I'm in the midst of doing some sizeable refactors (yay Unit Test!) while trying to expand the functionality of the devices.

[formlesstree4]

Unfortunately I'm not good at writing UI's for a complicated feature such as this. I don't know if I can finish this issue at this time until I get better at UI work.