esp8266 port now has working raw and friendly REPL, as well as working
soft reset (CTRL-D at REPL, or raise SystemExit).
tools/pyboard.py now works with esp8266 port.
User instances are hashable by default (using __hash__ inherited from
"object"). But if __eq__ is defined and __hash__ not defined in particular
class, instance is not hashable.
Having NotImplemented as MP_OBJ_SENTINEL turned out to be problematic
(it needs to be checked for in a lot of places, otherwise it'll crash
as would pass MP_OBJ_IS_OBJ()), so made a proper singleton value like
Ellipsis, both of them sharing the same type.
From https://docs.python.org/3/library/constants.html#NotImplemented :
"Special value which should be returned by the binary special methods
(e.g. __eq__(), __lt__(), __add__(), __rsub__(), etc.) to indicate
that the operation is not implemented with respect to the other type;
may be returned by the in-place binary special methods (e.g. __imul__(),
__iand__(), etc.) for the same purpose. Its truth value is true."
Some people however appear to abuse it to mean "no value" when None is
a legitimate value (don't do that).
* UDP currently not supported
* As there is no way (that I know of) the espconn_regist_connectcb()
callback can recognize on which socket has the connection arrived,
only one listening function at a time is supported
Remove unused and unneeded functions, also create Pin.get_config() that
returns the whole configuration of the pin.
This reduces code size by ~500 bytes.