mp_obj_get_type_str(): Handle MP_OBJ_QSTR.
objstr: More support for MP_OBJ_QSTR.
unix file: Refactor and add sys.stdout/stdin/stderr.
sequence.c: Start to refactor sequence operations for reuse among types.
Implement string multiplication.
str: Implement proper string (instead of byte string) indexing.

Also, support negative indexes.
Implement str.split(None).

Note that splitting by explicit string is not implemented so far.
run-tests: Allow to run tests selectively via command line.
Revamp qstrs: they now include length and hash.

Can now have null bytes in strings.  Can define ROM qstrs per port using
qstrdefsport.h
Merge branch 'master' of github.com:micropython/micropython

Conflicts:
	py/objstr.c
	py/py.mk
	py/stream.c
	unix/main.c
	unix/socket.c
Add len() support for arrays.
array: Implement iterator.
Add bytearray basic tests.
Add MP_OBJ_TYPE(o) accessor.

Should not be overused, but when needed, it's needed.
rt_is_true(): Start with testing for (expected) boolean values.
Add rt_resolve_method() which doesn't throw exception if method not found.

Unlike previosuly existing rt_load_method().