core 3.0: SRC machines that describe their own page (Digitakt mk1)

The core for the Digitakt mk1, version 3.0, built from mods/core at 7e69dc0 (3.0 since #57). This is a pre-release. The page and the apps keep taking their built-in cores from the latest release (v0.4.0) until the next one.

file	OS
core-3.0.elemod	1.53
core-3.0-os1.54.elemod	1.54

What 3.0 is:

• Core 2.1 and more. The same 39 sites with the same bytes, the same events and tables (the machines list included), and every 2.1 symbol where 2.1 has it. A mod built for 2.1 links with 3.0 unchanged.
• Firmware locations as exports (fw_track_blocks, fw_voice_params, fw_kit, fw_blit and the rest): a mod that names these instead of addresses builds for 1.53 and 1.54 from one source, with an empty 1.54 port (ADAPTING.md, "Firmware locations").
• Machines that describe their own SRC page (core_machine_ui). With the machine-pages mod drawing those pages, machine mods no longer hook the same firmware places, so several of them go in one build (ADAPTING.md, "Machine pages"). machine-pages is a mod, not a core, and is not attached here; examples/sine-machine is a whole machine to start from.

Using it:

• Which core a build takes: 3.0 only for a mod that needs it ("resources": {"core": "3.0"}, or needs_core in the shop's list). Every other Digitakt mk1 selection keeps 2.1, so today's builds keep their bytes: every selection of the shop's Digitakt mods links with 3.0 as it does with 2.1 (78 on 1.53, 66 on 1.54).
• Desktop apps (v0.4.0): add the file like a mod and tick it in place of the built-in 2.1.

Checked in digikit's emulator, against stock: core 3.0 alone, cold booted on 1.53 and on 1.54: every stage passes and all nine screens are identical. So is the audio, but for the recording's silent end, a millisecond longer, as with core 2.1.

On a unit: this exact core-3.0-os1.54.elemod ran on a Digitakt mk1 on OS 1.54, with machine-pages, NEIGHBOR, DIGISLICER, SOPHIE, Digi Mono, Digi Poly and digihealth in one build, and everything worked.