v0.24

Release Notes:

• Index-cue generated Kryoflux and SCP image files
  • Most external tools and emulators fail with non-cued streams
• gw write: New precomp command-line option (see the wiki)
• gw: Backward compatibility with older firmware (only back to v0.23)
• Safer bootloader update (CRC check before erasing existing bootloader)