Replace some Makefile commands with variables in py/mkenv.mk
Merge remote-tracking branch 'upstream/master' into makefile-tweaks
Add tests for sorted() function
and check that sorted(list) produces same output as list.sort()
Modify set tests to print sorted sets directly
instead of creating temporary lists and sorting those in-place
Merge pull request #444 from lurch/test-sorted

Add tests for sorted() function
py: Detect unmatched tripple quote in repl helper.
Merge pull request #445 from lurch/test-sorted-sets

Modify set tests to print sorted sets directly
Merge pull request #439 from lurch/makefile-tweaks

Makefile tweaks
windows: Make it compile with latest changes to py core.
Add uPy welcome message to UNIX and Windows ports; update Teensy port.

Partly addresses issue #154.
Add string formatting support for longlong and mpz.
README: Be specific that ARMv7 Linux is supported.
Fix truncation problem when using longlong implementation.
Merge pull request #447 from dhylands/str-format-mpz

Add string formatting support for longlong and mpz.
py: Rename pfenv_print_int to pfenv_print_mp_int, and add back former.

stmhal relies on pfenv_* to implement its printf.  Thus, it needs a
pfenv_print_int which prints a proper 32-bit integer.  With latest
change to pfenv, this function became one that took mp_obj_t, and
extracted the integer value from that object.

To fix temporarily, pfenv_print_int has been renamed to
pfenv_print_mp_int (to indicate it takes a mp_obj_t for the int), and
pfenv_print_int has been added (which takes a normal C int).  Currently,
pfenv_print_int proxies to pfenv_print_mp_int, but this means it looses
the MSB.  Need to find a way to fix this, but the only way I can think
of will duplicate lots of code.
unix, windows: There's no "help" builtin.
unix, stmhal: Consistently use "FileIO" as class name for file objects.

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