Dump Focusrite Scarlett intermal mixer to YAML (and load it back)

[tseaver]

I picked up a used 1st generation Scarlett 18i20, and needed a way to persist my configuration (since the ALSA-based changes don't get written to the flash). I poked around with @x42's 'scarlett_mixer', and got it working by changing all his hardcoding to match the 18i20 values. I found that unsatisfactory both at the code level, and in the UI, where the extra output gains and mixes got a bit unweildy.

So, I have created a 'scarlett_yaml.py' script for that purpose. It *may* work for other interfaces with internal mixers, at least if they support ALSA. Check it out on Github https://github.com/tseaver/scarlett_yaml.

The YAML "schema" is pretty straightforward. I checked in my default configuration as well: https://github.com/tseaver/scarlett_yam ... fault.yaml. I can dump it, edit the file, and reload to make changes, and even check in different configurations to version control, or save them in a recording project folder.

Hope someone else here may find it useful.