* In unbrick mode, revert previous change that left the processor hanging.

Make minichlink able to be usd as a library + let it read/write debug registers on the device directly from command-line.

 * Document _write

Add ability to use vendor commands with programmers.

* Blink now blinks D4 too
* Don't use compressed instructions by default.  Some compilers are old.
* Prevent double-halting on linke programmer.

getttting reallyyy close to working esp32s2 - I can now write ram well.  Need to explore flash weirdness.