non-realtime buffer manipulation commands

[catfact]

things like "copy/mix" would be useful additions to buffer "clear, read, write" &c. functionally very straightforward.

additions required for glue layers:

on the crone/c++ side:

(note that for this we don't need to add to Commands enum because there is no work to do on the audio thread.)

• BufDiskWorker request/perform methods (where the work actually happens)
• SoftcutClient method
• OscInterface lambda

and then on the lua/matron/C side:

• weaver.c function
• softcut.lua function

[tehn]

@catfact did you have additional commands you wanted added? or did @csboling cover this?

[catfact]

i can imagine plenty of other things, but this is not a priority. i like it as a "good first issue" to encourage potential contributors to get their feet wet with the audio cpp code in a non-realtime environment. if you're trying to purge the issue list of non-bugs, then i guess close it by all means. i have no personal desires here.

[tehn]

i agree it's a good first issue!

i was suggesting that if we were to indicate a few NRT processes we wanted it'd be a better first issue.

ie, NRT gain changes? or normalization?

not trying to simply purge the list of non-bugs... just making an attempt to establish a more focused roadmap

[catfact]

gain change and normalization would be obvious ones that have been explicitly mentioned