Implementation for parsing 'exec'
Minor measure_loc improvements
Forgot to add this
Should check this at the end to at least identify the issue rather than giving bogus results
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%
fixes #238 improve Debug linking time by building LLVM -O3
-this significantly reduces the size of the resulting object files
cmake automatically use ccache if found
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