Add Support for Bass Guitar Notes

[TheCococQuartz]

Is your feature request related to a problem? Please describe.
Its not a big problem, but I've written a song recently that had a guitar playing many notes that are out of range, since there are bass guitars that can play notes lower that what this program can visualize, I believe that these notes should be accounted for.

Describe the solution you'd like
If any guitar instruments are identified in any channel (MIDI patches 25-32 and 34-40), there should be an option in the GUI to change any of those channels to bass tuning (ie. change the Slap Bass 2 in channel 4 to bass tuning). This would be shown by having the strings on said guitar be more thicker.

Describe alternatives you've considered
You could also not do this, I guess.

[wyskoj]

Guitar and BassGuitar will automatically use a drop D tuning if there is any note below the instrument's lowest E. This is shown by that tuning peg being rotated.