2. Delay and don't clear halt request when unbricking.

also check if the target is connected, instead of reading nonsense in the void
and cherry on top, check for -h flag at the top to avoid plugging something to get help

Signed-off-by: bmx <none>

 * Add extra wait when flashing.

 * 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.