[Open_electroporator] pyflex_f401 v0.5 --> v0.6 testing

[John Griessen]

The last few days have been tough, no luck with the STLINK debugger, no good observations.  Besides flailing with STLINK, I found 
some things wrong with platform definition and fixed them.
Today I hooked up a USB to dual serial port chip by FTDI that is a standard way to make various JTAG/SWD debuggers
for ARM MCUs.  I used it to load code and got some good feedback from openocd program and will test further in AM,
sending commands to toggle LEDs, attempting to get a micropython REPL on one of the serial ports.  I can load micropython, and 
with startup program to run, set which serial port and a low speed like 19200 baud, so it can run fine with internal resonator,
then go from there debugging with much more speed than without REPL.