Discover all module-level numeric constants.
fix for #622 - support start in enumerate
tweaked registry + stacking implements for functions
Unify resolution of python value during typing
slightly better name to access the wrapped function in implement.
Remove local import.
- move ctypes_utils and cffi_support code into numba.typing
- old files aliases to new location for backward compatibility
no need to getattr on an attribute known to be there.
changed implement stacked register from recursive to iterative.
added assert in make_enumerate_object
raise an error in type inference if enumerate has more than 2 args

Note: relies on the python interpreter raising the error.
Merge pull request #623 from numba/622-fix

fix for #622 - support start in enumerate
Merge pull request #619 from sklam/altfix524

Alternative fix for #524: Discover all module-level numeric constants.
Merge branch 'master' of github.com:numba/numba into cfunc_lifetime