These modules would be very handy to have in order to implement a
more robust replacement for ampy. It costs around 2KiB of text and
no data or bss.
'binascii' has base64 encoding, which can be used to create a fully
8-bit-clean transport above the slightly cooked serial connection of
these boards.
'hashlib' is a bit less critical, but I have found it handy to
be able to robustly checksum remote files.
I see this as only being useful on ports which don't have USB block
device support, so atmel-samd doesn't need it. These modules are
already on esp8266 so I think nrf52 seems like the only one that
needs it.
.. defaulting to off for circuitpython-supported boards, on for others.
.. fixing up the tests that fail when it is turned off, so that they skip
instead of failing
1. Turn off MICROPY_CPYTHON_COMPAT, which includes a number of minor CPython compatibility features,
most of which have workarounds, but uses up significant flash.
2. Turn on MICROPY_PY_SYS_MAXSIZE, which implements sys.maxsize.
3. Turn on MICROPY_CAN_OVERRIDE_BUILTINS, which implements "_" as the most recent value in the REPL,
and also enables redefining builtins.
