Add option to auto-select Koch lesson after symbol is keyed correctly multiple times in a row

[JosePadron]

Related to https://github.com/oe1wkl/Morserino-32/issues/45

• [x] Add new menu.
• [x] Add logic for auto-select new Koch lesson.
• [x] Bench test.

[oe1wkl]

Jose, this will require some testing before I can commit it.

[JosePadron]

Jose, this will require some testing before I can commit it.

I understand. Let me know if you need anything else from me.