This both lets us reuse the frame object and verify
that the BoxedFrame is still valid.

Conflicts:
	src/codegen/unwinding.cpp
	src/codegen/unwinding.h

The first change is to move to a PIMPL strategy so that
we can provide a more extensive unwinding API to other modules.
In particular, you can get access to a python frame iterator
and make repeated calls on it.  This is in preparation of the
sys._getframe implementation.

This also exposed an issue with our usage of libunwind -- basically
you have to do all of your unwinding in one function, but we were
doing it in several different functions and happening to get away
with it.  So, switch from a C++11 range-for loop which is nicer, to
a callback approach which is less nice in my opinion, but safer.

fix recursive searching problem in Makefile

Update README.md

strip U out of the mode passed to fileNew before calling fopen

-fix link to Makefile
-update -x argument to current usage

Conflicts:
	from_cpython/Lib/collections.py
	src/codegen/irgen/irgenerator.cpp

support 'linux2', 'darwin', and 'unknown' for sys.platform

Conflicts:
	src/runtime/builtin_modules/builtins.cpp
	src/runtime/import.cpp

split cmake_check to cmake_check and clang_check

Fix a couple misc issues along the way

The callers were assuming that the module represents the globals,
which is not always true.

We can currently fetch globals from the interpreter, but not the jit.
We don't allow custom globals through the jit, so for now we can just
return the module; I think we should be able to support the jit by adding
the globals as a stackmap arg.

We should be able to support them in the JIT, but do the easy thing
for now.

also, put the globals info on the ScopingAnalysis instead of ScopeInfo

All the old prints still exist, but at -vv or even -vvv mode.

The basic system is:
-v mode gives information about the overall execution: what functions we
    run into, what things take longer than we expected, etc.
-vv mode gives information about each function: the cfg, llvm ir, etc.
-vvv gives information about each BB.

cmake configure script

The builtin functions in the `operator' module are missing their
__name__ attribute, which is causing some of the imported CPython
regression tests to fail.