Improving output formatting in codegen_objc.py.
Reactivating output for Python import statements in codegen_objc.py. 
They are emitted as comments.
Adding CLI attribute support to main in codegen_objc.py.
Rewriting function emission to be more flexible.
Moving utility functions out of class scope.
Improving visit_FunctionDef().
Adding CLI attribute support to main in codegen.py.
Adding comment in codegen_objc.py.
Merging improvements/bug fixes with those in https://github.com/mitsuhiko/pyastutil.
Merging changes to codegen into codegen_objc.
Moving codegen’s symbol mapping to separate file.
Moving codegen_objc’s symbol mapping to separate file.
Changing to selective import in codegen.
Changing to selective import in codegen_objc.
Rewriting using StringIO.
Updating file headers.
Fixing empty else statements.
Fixing typo.
Merge remote-tracking branch 'refs/remotes/origin/master'