Available via sys.std{in,out,err}.  Basic reading and writing supported.
Even sys.stdin.readline!

Should address issue #475.

Must use mp_obj_get_type to get the type of an object.  Can't assume
mp_obj_t is castable to mp_obj_base_t.

Pass a single parameter (doesn't matter what): pyb.info(1), will dump
the GC alloc table.

Also contains raw memory read/write functions, read8, read16, read32,
write8, write16, write32.  Can now do:

stm.write16(stm.GPIOA + stm.GPIO_BSRRL, 1 << 13)

This turns on the red LED.

With the new constant folding, the above constants for the GPIO address
are actually compiled to constants (and the addition done) at compile
time.  For viper code and inline assembler, this optimisation will make
a big difference.  In the inline assembler, using these constants would
not be possible without this constant folding.

Can now calibrate, set pulse width, angle and speed.

SW and X17 now both map to PB3

If no nlr_buf has been pushed, and an nlr_jump is called, then control
is transferred to nlr_jump_fail (which should bail out with a fatal
error).

Full CPython compatibility with this requires actually parsing the
input so far collected, and if it fails parsing due to lack of tokens,
then continue collecting input.  It's not worth doing it this way.  Not
having compatibility at this level does not hurt the goals of Micro
Python.

They correspond to io.FileIO in io module hierarchy (with small caveat
that io.FileIO is raw file and works with bytes, not strings).

Also add command line option to unix port to select emitter.

This is to reduce ROM usage.  stream_p is used in file and socket types
only (at the moment), so seems a good idea to make the protocol
functions a pointer instead of the actual structure.

It saves 308 bytes of ROM in the stmhal/ port, 928 in unix/.

Finishes addressing issue #424.

In the end this was a very neat refactor that now makes things a lot
more consistent across the py code base.  It allowed some
simplifications in certain places, now that everything is a dict object.

Also converted builtins tables to dictionaries.  This will be useful
when we need to turn builtins into a proper module.

Towards addressing issue #424.

Had a small increase to ROM usage (order 60 bytes).

This does not affect code size or performance when debugging turned off.

To address issue #420.

Which are ESC O H, ESC O F.

Home/end work in picocom and screen (different codes in those 2
programs).  Also, CTRL-A (for non-empty liny) and CTRL-E act as
home/end.

This adds readline(), readall(), etc. methods. Also other fixes to make
Python API compliant and "with" support.