Updated teensy to use common code from stm directory.

Updated mconfigport.h to enable GC
py: Improve __build_class__.
Merge pull request #111 from dhylands/teensy

Updated teensy to use common code from stm directory.
Merge branch 'master' of github.com:dpgeorge/micropython
Move lexerstr to main py directory (everyone uses it).
Merge pull request #112 from iabdalkader/master

Use LSI OSC for RTC clock when LSE is not detected
Add support for stream and buffer protocols.

Stream protocol is abstraction of serial I/O. Buffer protocol is
abstraction of random-access I/O. These protocols are defined down
to C level, to allow generic, while still efficient algorithms
to be coded in C (like, buffered transfer between 2 stream objects,
saving/loading of buffer object to/from stream, etc). (Note that CPython
define buffer protocol on C level, but apparently not stream protocol).
Add generic implementations of Python read()/write methods for streams.

These can be used for any object which implements stream protocol
(mp_stream_p_t).
unix: Add basic implementation of io.FileIO object.

Note: only read/write/close methods are defined so far, and class
is not exposed (use open() factory function, as usual).
Update stm/Makeile to use OBJCOPY and SIZE macros

While updating the teensy Makfile, I noticed that the stm Makefile
was using calling arm-none-eabi-objcopy and size rather than
$(OBJCOPY) and $(SIZE), so I added these 2 for consistency.
Update teemsy/Makefile to use py.mk

I also fixed main.c to compile with the new str lexer
py: Stuff qstr in object pointer; keys for mp_map_t are now always mp_obj_t.
Merge pull request #118 from dhylands/stm-use-OBJCOPY-SIZE-macros

Update stm/Makeile to use OBJCOPY and SIZE macros
Merge pull request #119 from dhylands/teensy-use-py.mk

Update teemsy/Makefile to use py.mk
Merge pull request #114 from pfalcon/streams-bootstrap

Define buffer and stream protocols, and other starting bits of io.* framework, with io.FileIO-like implementation for Unix
py: add variable argument exception constructor function.

Addresses issue #104.
Make build output quieter.

Use make V=1e make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.

This should fix issue #117
py: Proper framework for built-in 'type'.
Merge pull request #120 from dhylands/make-build-quieter

Make build output quieter.
Add string comparison tests.

Use computed string to exercise string interning code better.