we're not very good at this :/

third time's the charm mayhaps

Allows interaction with the MicroPython REPL when GDB debugging is
selected via DEBUG_GDB_ENABLED.

This also allows to flash the flow3r without having to press a button.
USB disk mode is not available in this case.

channels are now dynamically allocated and can be garbage
collected. note that channels do NOT live on the mp heap
so their memory footprint won't trigger a gc, we rely on
pyst3m just doing that on its own every now and then.

- sequencer value mode fixes
- better rms

this is a bit preliminary, st3m media is a bit halfassed
and line in isn't supported at all, but it's a good start

- system volume per channel
- rms tracking per channel

for some reason we're getting really bad
think times. will look into a proper fix soon,
this here is just a band aid for longer texts.

This adds the .get_help() method to views.
application writers can use this to return
context-dependent help strings to be displayed
by the system menu.

In the future this API could also be used to
return more complex objects but this makes
for a good start :D