Add mux_vbat information for bs* targets.
Add support for HobbyKing DIY Open ESC boards (unreleased rev 0).

Not built by default.
Add support for AfroESC 3 boards.
Upgrade m8def.inc to v2.35 and mute pragma ignored warnings from avra.

This should allow building without warnings with avrasm2.
Add a knob to disable RC pulse calibration if desired.
Properly support USB linker on ICP pin.
Correct the LED order.
Add support for MikroKopter BL-Ctrl v1.x boards (tested on v1.2).
Add support for newer TQFP RCTimer 50A boards ("rct50a2").

This is untested since I do not have the board, and those who do are on
holiday.
Fix build error detection.
Set diy0.hex build dependencies.
Simplify MOTOR_REVERSE case.
Generalize diy0.hex build dependencies.
Add support for Hacker/Jeti Master 135-O-F5B boards (12MHz).
Fail if the given board define is not recognized.
Fix build regression for /bin/sh -> dash cases since 5a5792a96.

There seems to be no way to do the same as "set -o pipefail" in dash.
Remove safemode disabling from avrdude command line.
Remove broken / extraneous RCTimer 50A v2 target (use hk200a).

The B-phase high/low were flipped, and when corrected, it matches "hk200a".
Turn off brake before beacon beeping to avoid short circuit.

Regression since beacon merge (a9c33723d8), when MOTOR_BRAKE enabled.
Fix building when MOTOR_REVERSE = 1 (since 934122d59).