Mutable Instruments DSP integration in PocketTracker Studio

Original DSP author: Emilie Gillet.
Original per-file copyright and permission notices are retained in the source.
Mutable-Instruments-MIT.txt contains the collected original notices.
Mutable-stmlib-LICENSE contains the original stmlib license overview.
PocketTracker's integration code remains under GPL-3.0-or-later.

Recorded vendor revisions (native/vendor/mutable/PROVENANCE.json):
eurorack: f4cfa7697095a28d292bff758beb51deb49b5a86
stmlib:   e3bd7c9cc00e4364166f9905c0509b6ffd0535ec

Compiled upstream implementation scope, native/studio/CMakeLists.txt:
  Plaits:   37 C++ implementation/resource files
  Rings:     6 C++ implementation/resource files
  Elements:  9 C++ implementation/resource files
  Warps:     5 C++ implementation/resource files
  Clouds:    7 C++ implementation/resource files
  Braids:    4 C++ implementation/resource files
  stmlib:    3 C++ implementation files (random, units, atan)
Total: 71 upstream C++ implementation/resource files, plus included headers.
All 71 retain their original MIT permission notices.

This is a software integration of selected DSP algorithms. It is not the
complete firmware or hardware behavior of the original modules. Parameter
mapping, sample-rate adaptation, preset banks and the application interface
are supplied by PocketTracker Studio. Their behavior can differ from the
original hardware.

The vendor tree also retains upstream embedded hardware, bootloader and
development support files. These are not compiled by the studio target.
Their original notices remain with those source files; no claim that every
file in the vendor tree is MIT-licensed is intended.