Navigation wait mode

[tgnorman]

This needs review in the context of the rotary encoder and 5-way nav button.

Questions:

• Should the rotary encoder be retained or replaced?
• Should the 5-way nav button be replaced with a simpler interface?

Tasks:

• Test the current navigation wait mode with the rotary encoder.
• Evaluate alternative navigation hardware.
• Update documentation based on the final decision.

[tgnorman]

Modified do_enter_process to include "wait" state. Also made next/prev encoder actions call go_back().
This avoids getting stuck, so encoder is once again functional... albeit clunky

[tgnorman]

Adding "wait" is not enough... I now think that the core problem is that my current TX Main do_enter and go_back code makes changes to the LCD, but does NOT actually alter the navigator class state. Still working this through...

It is also unclear if my system of remembering indexlevel is contributing to the mess