Just adjust line-endings of micropython.exe output, the rest should be
handled by Wine (automagically on properly configured distro).

To run:

MICROPY_MICROPYTHON=../windows/micropython.exe ./run-tests

Adds just 60 bytes to stmhal binary.  Addresses issue #362.

This fixes FORCED_EXIT internal flag leaking into Windows exit code.

acoshf, asinhf, atanhf were added from musl.  mathsincos.c was
split up into its original, separate files (from newlibe-nano-2).
tan was added.

All of the important missing float functions are now implemented,
and pyboard now passes tests/float/math_fun.py (finally!).

N (mod 4) is 0..3

Name choosen per latest conventions and for compatibiity with stmhal port.

Addresses issue #1006.

Otherwise, new tests are forgotten to be added to explicit lists. Issue
found running on Debian/ARM.

You can now assign to the range end variable and the for-loop still
works correctly.  This fully addresses issue #565.

Also fixed a bug with the stack not being fully popped when breaking out
of an optimised for-loop (and it's actually impossible to write a test
for this case!).

Now you can assign to the range variable within the for loop and it will
still work.

Partially addresses issue #565.

Issue was with uPy: on local machine with micropython-lib installed, io
module is available.  Not the case on Travis CI, where only _io module
is available in uPy.

TODO: Figure out what's wrong on Travis.

It's used by stmhal, but not unix.

This patch adds a configuration option (MICROPY_CAN_OVERRIDE_BUILTINS)
which, when enabled, allows to override all names within the builtins
module.  A builtins override dict is created the first time the user
assigns to a name in the builtins model, and then that dict is searched
first on subsequent lookups.  Note that this implementation doesn't
allow deleting of names.

This patch also does some refactoring of builtins code, creating the
modbuiltins.c file.

Addresses issue #959.