Main reason for expanding buffer protocol API was to support writes to a
buffer in ADC module (see read_timed). With this change you can now
create an array of arbitrary type and ADC.read_timed will store into
that array in the correct format (byte, int, float). I wonder though if
all these changes were really worth it to support just this function.
Hopefully this enhanced buffer protocol API (with typecode specified)
will be used elsewhere.
This is an attempt to clean up the Micro Python API on the pyboard.
Gpio functionality is now in the Pin object, which seems more natural.
Constants for MODE and PULL are now in pyb.Pin. Names of some
classes have been adjusted to conform to CamelCase. Other
miscellaneous changes and clean up here and there.
When querying an object that supports the buffer protocol, that object
must now return a typecode (as per binary.[ch]). This does not have to
be honoured by the caller, but can be useful for determining element
size.