Which allows you to run "make -C stmhal flashboard" from the top-level directory.
Also ties in nicely with my configurable BUILD directory from #506

This documentation is now available at micropython.org/doc/

Initial support for subclassing native types

It's not enabled by default because it doesn't fully work.  It can
connect to an AP, get an IP address and do a host-lookup, but not yet do
send or recv on a socket.

Also give proper error message when trying to construct a non-existent
LED.

Addresses issue #530.

And this is not good.

Biggest part of this support is refactoring mp_obj_class_lookup() to return
standard "bound member" pair (mp_obj_t[2]). Actual support of inherited
native methods is 3 lines then. Some inherited features may be not supported
yet (e.g. native class methods, native properties, etc., etc.). There may
be opportunities for further optimization too.

Decided to write own script to pull documentation from comments in C code.
Style for writing auto generated documentation is: start line with ///
and then use standard markdown to write the comment.  Keywords
recognised by the scraper begin with backslash.  See code for examples.

Running: python gendoc.py modpyb.c accel.c adc.c dac.c extint.c i2c.c
led.c pin.c rng.c servo.c spi.c uart.c usrsw.c, will generate a HTML
structure in gendoc-out/.

gendoc.py is crude but functional.  Needed something quick, and this was
it.

Even of these, some features do not yet work as expected.

This implements checking of base types, allocation and basic initialization,
and optimized support for special method lookups. Other features are not yet
supported.

Had choice of either interning or forcing full equality comparison, and
chose latter.  See comments in mp_map_lookup.

Addresses issue #523.

Addresses issue #526.

Of course, keywords are turned into lexer tokens in the lexer, so will
never need to be interned (unless you do something like x="def").

As it is now, the following on pyboard makes no new qstrs:

    import pyb
    pyb.info()

Also, clear up freed slots in containers.

As a follow up to 32bef315.

They either succeed or raise exception.

It's the same as LOAD_CONST_STR.

Remembering the last op is rarely needed, and when it is, can simply use
*save_ip.

Messages are still explanatory, while taking a little less ROM.

New way uses slightly less ROM and RAM, should be slightly faster, and,
most importantly, allows to catch the error "non-keyword arg following
keyword arg".

Addresses issue #466.

Implements 'def f(*, a)' and 'def f(*a, b)', but not default
keyword-only args, eg 'def f(*, a=1)'.

Partially addresses issue #524.

This is a small optimisation to zero out only the additional bytes that
the caller did not ask for.

Few other strings move to core, but make depend on "io" module.