Also added test for modtime.

Now you can use time.localtime on the timestamps presented by os.stat

Because (for Thumb) a function pointer has the LSB set, pointers to
dynamic functions in RAM (eg native, viper or asm functions) were not
being traced by the GC.  This patch is a comprehensive fix for this.

Addresses issue #820.

Also provides setraw() function from "tty" module (which in CPython is
implemented in Python). The idea here is that 95% of "termios" module usage
is to set raw mode to allow access to normal serial devices. Then, instead
of exporting gazillion termios symbols, it's better to implement it in C,
and export minimal number of symbols (mostly baud rates and drain values).

ROM down by 320 bytes on stmhal.  RAM down by 5.5k for a decompression
object.

This allows to make strings longer than 64k.  It doesn't use any more
RAM with current GC because a str object still fits in a GC block.

This simple patch gives a very significant speed up for memory allocation
with the GC.

Eg, on PYBv1.0:
tests/basics/dict_del.py: 3.55 seconds -> 1.19 seconds
tests/misc/rge_sm.py:     15.3 seconds -> 2.48 seconds

unix: Added install/uninstall

Put some code into the first 16K of flash

This basically shrinks the remaining size of flash in the portion
that goes after the internal flash drive.

Also fix unix port so that SystemExit with no arg exits with value 0.

It's still "safe" because no scripts are run.  Remove the SD card if you
want to access the internal flash filesystem.  Addresses issue #616.

Also: remove obsolete pyb.source_dir setting, and reset pyb.main and
pyb.usb_mode settings on soft-reset.

Waiting for 1000ms between seconds of RTC is sometimes too quick.
Waiting for 1001ms is enough for the RTC to pass 1 second.

Saves over 35k ROM due to elimination of unused HAL functions.  All
tests pass.

Addresses issue #702.

Updated teensy/README.md to reflect change in build process (teensyduino is no
longer required for build).

Viper functions can now be annotated with the type of their arguments
and return value.  Eg:

@micropython.viper
def f(x:int) -> int:
    return x + 1

Some small code clean-ups that result in about 80 bytes ROM saving for
stmhal.

msvc: Use built-in alignof

Multiplication of a tuple, list, str or bytes now yields an empty
sequence (instead of crashing).  Addresses issue #799

Also added ability to mult bytes on LHS by integer.

This also fixes a 'unnamed type definition in parentheses' warning on the
alignof implementation define in binary.c

The only change is line-ending convesion to LF.

Also disable gc module on bare-arm port.

Also fixes compiler error in moductypes when compiled without debugging.

Addresses issue #778.

Can now index ranges with integers and slices, and reverse ranges
(although reversing is not very efficient).

Not sure how useful this stuff is, but gets us closer to having all of
Python's builtins.