Update some parts and add boot loader information.
Fix some board comment mistakes.
Erase non-boot portion of flash when chip erase command is received.

This works around bugs in avrdude that verify portions of flash that were
never flashed, assuming chip erase is sent (the default). However, the
boot loader will still fail verification when updated through itself
(meanwhile, avrdude is fixed in SVN).
Invert POWER_OFF to POWER_ON so that POWER_OFF does not need to be initialized.

This may also fix (or break) the MK i2c two-byte protocol, which was
relying on POWER_OFF to be set when first connecting.
Disarm after 2 seconds of signal loss.

Also beep when this occurs instead of immediately after signal loss.

This may mask some signal corruption issues and make it look like power
jitter instead, but this seems to be safer overall.
Use the LEDs on boards which have them.
Fix double-reverse (no reverse) for i2c and UART (since 934122d59).
Move pwm_off_again logic to pwm_again, reducing full throttle bump.

MIN_DUTY is offset by 2 cycles, but we still have a lot of room.

This also saves some otherwise-repeated logic.
Fix starting in the case of PWR_MIN_START == PWR_MAX_START.

No assembler output change with the default settings.
Support configurable dead time when complementary PWM is enabled.
Support assisted jumping to any boot loader, regardless of if the
Turnigy USB linker-compatible one was included at build time.

This allows mixing and matching of any boot loader that fits, without
requiring the boot loader to be caught only at power-up.

The included boot loader can be installed once and the main flash area
updated with build without BOOT_LOADER set. As long as BOOT_JUMP is set,
we will jump to a boot loader, if present, when the PWM input pin stays
high.
Fix propagated FET port typos (no output change).
Add support for TBS 30A ESCs (ICP input version).
Add a few more boards.
Work around avrdude <= 5.11.1 verification bugs.

Since 50ac1b7a, we try to work around verification bugs exposed when the
program area shrinks by actually implementing flash clearing on when chip
erase is requested. However, since we can't clear the boot loader, this
ends up moving the problem to there. To solve all cases except where chip
erase is skipped (-D), pad the boot loader so that there are no gaps.
Remove -D from program_tgy_% target to work around avrdude verification bugs.
Correct voltage sense resistance.
Reduce voltage sense fraction to lowest terms.
Reduce manual 8-bit immediate manipulation into macros. No output change.
Update PWM interrupt comment, outdated since a1fb7afc1.