Add a direct GPIO example (compatable with 8 pin package)

Switch Makefiles to default to flash.

README: added "make flash" and linux info

Support more types of OLED displays

Updated for SysTick IRQ example for latest changes in ch32v003fun library.

Fix spacing to clarify behavior, and, also, improve algebra for microseconds. If a delay is much too long it at least has a shot at having a compiler warning.

Redo reverted patches for MacOS 

Remove .h files, pull code into top, clean up GPIO setup.

 * 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.