remove print "flush" arguments in examples -- not accepted by CirCuitPython

[jerryneedell]

The examples use the argument "flush=True" in many of the print statements but this is not recognized but CircuitPython and it throws an error.

[jerryneedell]

This appears to be A bug in CircuitPyhton and should be fixed there
adafruit/circuitpython#4888
leaving open until it is

[tekktrik]

Looks like the decision was to remove the flush argument in the examples then! Adding the "First Good Issue" label so it gets tagged for Hacktoberfest!