Add skeleton implementation of array.array and bytearray.

So far, only storage, initialization, repr() and buffer protocol is
implemented - alredy suitable for passing binary data around.
Add lean ("raw") socket module.
Add source file name and line number to error messages.

Byte code has a map from byte-code offset to source-code line number,
used to give better error messages.
Merge pull request #192 from pfalcon/arrays

Add skeleton implementation of array.array and bytearray.
Merge pull request #194 from pfalcon/socket

Add lean ("raw") socket module.
Add objarray.h .
py: Fix VM/runtime unpack sequence bug, Issue #193.
Merge branch 'master' of github.com:micropython/micropython
Fix warnings about int/pointer casting.
Tiny optimisation in objlist.c; a new test for inheritance.
py: Temporary fix for bug where not enough VM state is allocated.
Add socket examples (simple HTTP client and server).
Fix incorrect prototype of mp_builtin_open() after args refactor.
py: Add module/function/class name to exceptions.

Exceptions know source file, line and block name.

Also tidy up some debug printing functions and provide a global
flag to enable/disable them.
Merge branch 'master' of github.com:micropython/micropython
py: Add full traceback to exception printing.
Change int to uint for n_args in function with variable arguments.
Move tests in basic/tests/ up one level preparating to multiple test dirs.
stm: Upgrade to latest CMSIS libraries.

CMSIS V3.01 -> V3.20. Now in stm/cmsis to keep separate from ST
libraries.
Add directory for I/O tests with basic test for file methods.