GitLab

* Fix LED pin enum, first one should start at 1
* Fix LED initialization typo

* Add a TARGET definition to Makefile (default PYBOARD).
* Add support for discovery LEDs in led module.
* Add support for discovery user switch in usersw
* Add EXTI interrupt handler for discovery user switch on (PA0).
* Parameterize led and usrsw modules pins and port.
* Issue #83

* Move user switch code from main.c into a separate module (usrsw)
* Add usrsw.c to Makefile

Now much more inline with how CPython does types.

Qstr's are now split into a linked-list of qstr pools.  This has 2
benefits: the first pool can be in ROM (huge benefit, since we no longer
use RAM for the core qstrs), and subsequent pools use m_new for the next
pool instead of m_renew (thus avoiding a huge single table for all the
qstrs).

Still would be better to use a hash table, but this scheme takes us part
of the way (eventually convert the pools to hash tables).

Also fixed bug with import.

Also improved the way the module code is referenced (not magic number 1
anymore).

Use the storage cache not only for writing but also for reading. This
avoids reading stale data and thus data loss.

So far, only start and stop integer indexes are supported. Step is
not supported, as well as objects of arbitrary types.

mpconfig.h will automatically pull mpconfigport.h.

import works for simple cases.  Still work to do on finding the right
script, and setting globals/locals correctly when running an imported
function.

* Chane dfu.py to use Python 3 syntax to avoid dependency on Python 2.
* Update Makefile to call python instead of python2
* Fix #33

A big change.  Micro Python objects are allocated as individual structs
with the first element being a pointer to the type information (which
is itself an object).  This scheme follows CPython.  Much more flexible,
not necessarily slower, uses same heap memory, and can allocate objects
statically.

Also change name prefix, from py_ to mp_ (mp for Micro Python).