crossfade

[fringd]

Okay. just looking at that #172 again it's too big. Here's a smaller one with just the cross fade

when pico 8 moves from one note to another it does a very fast short crossfade to keep clicking out of the sound. here you can see the curves as a channel switches notes before this pr, after this pr, and in pico8 actual: note the vertical discontinuity ~75% of the way through the first sample. this will sound like a pop.

and here are the wav files if you want to listen to them. this is the same baseline played pre-patch post-patch and on pico8 you'll here a lot of popping noise in the pre-patch sound: audio.zip

• [x] This pull request is for a single Feature or BugFix
• [x] Your code builds clean without any errors on all platforms
• [x] You have added unit tests (if this is a change to the core Pico 8 emulator)

[fringd]

yeah no worries! it was kind of a beast to review all merged. I've got the custom instruments broken out I'll dust it off and send it in soon ^_^