Cleaned up menu (pylint)
Updated checking for TX when plotting and how plotting handles multiple requests.
Code checks if item is currently active in a telnet thread, and then launches. If not it adds the thread.
It then displays the dialog, the dialog receives the mse values via pub-sub so you can have multiple dialogs listening to a single thread, similar to how DGX serial works.
Updated MSE baseline display addressing issue #31, issue #22, and issue #21
Caught MSE values that are -255 and set them to 0 ( these are when the unit is unlinked)
addresses issue #24
Set default MSE to N/A until we get a value