Channel/octave in MTS-ESP mode

[Andreya-Autumn]

• Allow channel per octave mode under MTS-ESP
• Show menu item when MTS-ESP is active
• Re-structure MTS-ESP tuning menu somewhat

[Andreya-Autumn]

This all works for me and checks passed. Please take a look in case I did something silly though. ;) As time permits of course.

[mkruselj]

LGTM!

[baconpaul]

Yup