Cosmetic: removed a surprising number of double semicolons.
Merge branch 'master' of https://github.com/kbob/kerfburn
Outlined e-stop and lid switch code.
Renamed config/*.d to .*.d.
Outlined the work for lid and e-stop switches.
Comment only.
Now calls trigger_fault on ^C instead of emergency_stop.
doc: ^C is ETX, not CAN.
Changed thruport baud rate to 115200.
Added [pin-name]_grp for interrupt pins.
Partially implemented safety switch handling.
Removed back/e-stop.c and .h.
Merged safety-policy.[hc] into safety.[hc].
Laser portion of real-time engine now respects safety policy.
Cleanup.  Added missing #include, removed dead code.
Updated the E-stop report (actually the safety report).
Cleanup.  Tweaked definition of timout_func.
Changed [interrupt pin]_PCIE_reg to _PCI_bit.
More notes about safety module.
Continued implementation of safety switches module.