* Run the DAC in 24bit mode.
* Update comment.
* Remove accidental paste
* Fix distortion.
* Shift up the samples into -1..1, not much different, but we get an extra bit of resolution at the low end.
* Attempt at optimizing so the new filtering runs better.
* Additional improvements.
* Further optimisations.
* Seems to work OK with 10 filters. Just noise with 11.
* Increase config buffer size, and make the bqf_transform function inline
* Remove extra loop and process input evently across both cores.
* Enable 15 band EQ.
* Shift some load of core1
* Revert buffer size change
* Mark USB transfer as done sooner.
* Fast multiply.
* Fix build failure.
* Rollback changes we dont need.
* Fix save config to flash
* Increase filter stages to 20. We cant quite run that many though.
* Replace a few doubles with floats. According to the raspberry-pi-pico-c-sdk manual, doubles are around 3 times slower than floats.