- FreeBSD provides alloca() via stdlib.h, in contrast to Linux and Windows
- Move the includes for alloca() intp mpconfigport.h
py: Add generic mp_not_implemented() func to use instead of assert().

Benefits: won't crash baremetal targets, will provide Python source location
when not implemented feature used (it will no longer provide C source
location, but just grep for error message).
modsys: Add optional support for sys.platform.

Ports which wants to have it, should define MICROPY_PY_SYS_PLATFORM to a
string value they need.
py: Implement default keyword only args.

Should finish addressing issue #524.
objtype: Enable __lt__ method support for instances.
Merge branch 'master' of github.com:micropython/micropython

Conflicts:
	py/emitglue.c
py: Make sure getattr() works with non-interned strings (by interning them).
tests: Fix default arg test.
py: Simplify function call of a bytecode object.
tests: Add more tests for default keyword-only args.
Merge branch 'alloca' of github.com:marcusva/micropython into marcusva-alloca
Provide definition of alloca() in mpconfigport.h.
Merge branch 'marcusva-alloca'
tests: Run 'micropython' tests on pyboard.
windows: Move include of malloc.h outside #ifdef msvc.
stmhal: Fix pyb.bootloader so it works for gcc-4.9.0.

See PR #618.
objtype: Optimize stack usage mp_obj_class_lookup().

As before, instead of pushing constant values on stack again and again, just
pass around pointer to a structure.
objtype: Fix passing of class param to inherited classmethods.

This is getting more and more tangled, but that's old news.