Core menu can be entered by powering up with space-bar held

[gurcei]

My daughter discovered this by her own accidental bash-testing.

I even recall on one of her bash-testing forays, she managed to jump straight into the flashing mechanism (skipping the initial core slot menu altogether).

Part of me feels like we might be able to replicate these issues with some bash testing ourselves.

[gurcei]

Other observations:

• While on the core slot menu, if I press c, b, d it surprisingly goes to a file chooser (to pick a core).

• pressing 'm' shows the flash monitor, but @gardners explained this is intended behaviour

[lydon42]

Todo

• [x] find all the keys that can launch the flasher and reduce to a minimum
• [x] moved to separate issue - use build target to decide to allow more keys (dev boards) or less (real machines)
• [x] add display of flasher/core version to the flasher screen.
  • no screenspace, so perhaps add a HELP menu.
• [x] currently HELP does flash a slot, because Ctrl-7 and HELP generate the same keycode
  • use D611 value to distinguish
• [x] make all non-user needed keys to key combos
  • [x] "any key" launches flash inspector on fail -> Ctrl-F
  • [x] M/m is flash inspector -> change to Ctrl-F