For some reason a portYIELD() is not enough to give the serial task the
option to run. I tried vTaskDelay() and that works. To not block more than
needed portYIELD() is still called when the queue is not full and only
call vTaskDelay() when it is full.

Closes #218

The MSC interrupts can come in back to back, effectively blocking
the FreeRTOS timer task which resets the watchdog. This simple fix
simply resets the watchdog when performing an MSC read or write.

The -EIO error was triggering a warning in the caller.

Also auto generate the header during build time.

Closes #211

Closes #208

Accessory Design Guidelines for Apple Devices says that TX power should
be included in the advertisement.

Also ask for the current time service in the scan report so the card10
shows up in the system dialog.

I don't trust the TRNG/PRNG combo inside the binary blob.