Implementation for parsing 'exec'
add two passes which remove unnecessary boxing
* the first one removes boxInt, boxFloat and boxBool calls where the argument is coming from a corresponding unbox call
* the second pass removes duplicate boxing calls inside the same BB

together they improve the performance by about 10%
Updates to the measure_loc tool
Merge pull request #243 from undingen/boxing_opt

add two passes which remove unnecessary boxing
Rename expr->body
Merge #213

With some changes
- renamed AST_Exec::expr -> body (to match CPython)
- removed references to AST_SetComp
Add copyright notice to this file
Make 'is_generator' be a property of SourceInfo, not ScopeInfo

ScopeInfo involves checking the whole function subtree to resolve
scoping references.  SourceInfo has information about the specific
function.  is_generator used to be in ScopeInfo, but accessing it
would require doing the full subtree analysis, which can be
unnecessary.

This lets us avoid analyzing function subtrees that are never entered.
'import a.b' results in a module called 'a.b'

Previously we were calling it just 'b'.
Attempt imports from the from_list

ie 'from a import b' now attempts an 'import a.b' if b does not already exist.
This also works for imports caused by__all__.
Add str.translate()
Guess we need to support the 2-arg form of str.translate() as well
Drat, will have to implement this
Improve super() handling
Try cutting down the number of test configurations
Didn't dup the node here

I'm not sure that we need to do this at the expression-level --
I think we just have to do it at the statement level.
hasattr() returns False if an Exception is thrown.
Harden the CAPI include files a bit

Remove some definitions that should no longer be in there
(structs for which we have Pyston-internal definitions).

Instead of doing "typedef void PyIntObject", do
"struct _PyIntObject; typedef struct _PyIntObject PyIntObject;"
which prevents spurious things like type conversions or
sizeof(void)'s.
Add structseq.{c,h} and sliceobject.h

Haven't added structseq.c to the build quite yet
Missed one