unix Makefile: -Og doesn't work (at least) with gcc 4.6 below.

Also, don't try to force debug info format, use native.
unix socket: Store module constants in data structure.

-147 bytes on x86.
unix socket: Add few more socket constants.
Add MP_OBJ_IS_INT(), for symmetry with MP_OBJ_IS_STR().
Functions of fixed number of args are special-cased only for 3 or less args.
unix socket: Add setsockopt() method.
sock-server.py: Use SO_REUSEADDR to avoid errors on quick restart.
stm: USB host mode working! Restructure stm library directories.
Merge branch 'master' of github.com:micropython/micropython
Merge pull request #226 from pfalcon/make-debug

unix Makefile: -Og doesn't work (at least) with gcc 4.6 below.
Change -Og to -O0 in unix-cpy/Makefile; cast to small int in socket.c.
Implement send() method for generators.
Merge pull request #228 from pfalcon/gen-send

Implement send() method for generators.
gen.send(): Throw StopIteration. Also, explicitly shutdown finished gen.

Otherwise, some generator statements still may be spuriously executed on
subsequent calls to next()/send().
list.pop(): Don't allow ->alloc drop to zero, which causes unexpected behavior.