Update menu code

[lenerd]

Hi everyone,

I have rewritten some of the menu code (see below). I would appreciate any feedback and if you have any suggestions, please let me know.

The changes cover about the following:

• The menu functionality now lives in Matrix/menu.py.
• The menu code is cleaned up and duplicated code is moved to separate methods.
• More error handling is introduced for the cases that configuration files are inaccessible or the user enters garbage.
• The user is asked for the protocol configuration once, which is then read from the file and passed to the other components as dictionary.