This Sketch demonstrates the use of a tool to print a stack dump
at reboot after a Hardware WDT event.

The module hwdt_app_entry.cpp writes a stack dump to the serial interface
after a Hardware Watchdog Timer has struck and a new boot cycle has begun.
The sketch must properly initialized the Serial port before the crash.

hwdt_app_entry.cpp is the core file that does the work.

Improved comments.
Added option to match the UART speed used by the sketch.
Added option to print greeting at the start to indicate the HWDT stack dump code is active.
Isolated logic for handling strings: one assuming they are not inited at
the time the code is running and one that does. The later appears to be the case.

Fix issue with HWDT reason detection when sketch crashes too fast.
Added sample sketch menu option for crashing with a function defined
with a weak attribute via prototype, but never actually defined in
full function form. eg. `void trouble(void){return;}`

Adjusted configuration option order for most likely to be used to the top.
Tried to improve comments.
Replace numbers with enum values.

Regular global strings have worked reliably.
Tweaked reset reason detection.
Reordered elements in global structure.
Improve #if test for debug option
Always improving comments.