Needs proper coverage testing.  Doesn't implement -ve & -ve.
Addresses issue #611.

Also unifies use of SMALL_INT_FITS macro across parser and runtime.

Addresses issue #627.

This reverts commit 6e76f7bc.

This patch tries to workaround a previous clang workaround. Instead of going
into workaround of workaround spiral, the original workaround should be tamed.

windows: Complete rename of MICROPY_PATH_MAX to MICROPY_ALLOC_PATH_MAX (...

Fix unix DEBUG=1 builds

Without this fix, I get the following error:

CC gccollect.c
gccollect.c: In function ‘gc_helper_get_regs’:
gccollect.c:63:1: error: bp cannot be used in asm here

This helps the compiler do its optimisation, makes it clear which
variables are local per opcode and which global, and makes it consistent
when extra variables are needed in an opcode (in addition to old obj1,
obj2 pair, for example).

Could also make unum local, but that's for another time.

Reorder interning logic in mp_obj_new_str, to be more efficient.

str_new is globally accessible, so should be prefixed with mp_obj_.

This removes need for some casts (at least, more than it adds need
for new casts!).

This completes non-automatic interning of strings in the parser, so that
doc strings don't take up RAM.  It complicates the parser and compiler,
and bloats stmhal by about 300 bytes.  It's complicated because now
there are 2 kinds of parse-nodes that can be strings: interned leaves
and non-interned structs.

Merge branch 'keep-strings-uninterned' of github.com:pfalcon/micropython into pfalcon-keep-strings-uninterned

Conflicts:
	py/parse.c

This means that complete slice operations are supported for lists (but not
for bytearray's and array.array's).

Older int-only encoding is not expressive enough to support arbitrary slice
assignment operations.

Addresses issue #598.

Now of the form MICROPY_PY_*.  See issue #35.

.makefile() should allow to specify which stream time to create - byte
or text.

Caveat is that __new__ should recurse to base class __new__, and ultimately,
object.__new__ is what handles instance allocation.

MP_ALLOC_* -> MICROPY_ALLOC_*
MICROPY_PATH_MAX -> MICROPY_ALLOC_PATH_MAX
MICROPY_ENABLE_REPL_HELPERS -> MICROPY_HELPER_REPL
MICROPY_ENABLE_LEXER_UNIX -> MICROPY_HELPER_LEXER_UNIX
MICROPY_EXTRA_* -> MICROPY_PORT_*

See issue #35.

Also, define object.__init__() (semantically empty, purely CPython compat
measure). Addresses #520.

Allow compilation of unix port under clang on OS X

See issue #608 for justification.