altboot:

altboot:
- Removed multiple die() functions
- Altboot no longer activates an off-flash altboot-menu when not
  booting from flash
- Added a debug_echo function which is disabled in non-rc and
  non-snapshot builds
- RC's and snapshots now spawn a debug shell on tty4 right after
  the kernel is booted
- die() messages are now colored red/white, debug is purple(?)/white
- Fixed start_networking() on collie and made it a little bit more verbose