Wrap bitwise like the rest of native

[eeue56]

Problem:

Having a bare return statement without a wrapping breaks a lot of build tools, because they try and load things as JS and get things wrong. These things are important to watch for build-tools, since that's how they know when packages have been upgraded and to re-run elm-make.

Solution:

Wrap the return statement with a function like the rest.

@evancz this is fairly important to be fixed before non-alpha release

[evancz]

Thanks. I can tell it is important ;) If someone imports Bitwise their Elm code would just not work at all.

[evancz]

Thanks. I can tell it is important ;) If someone imports Bitwise their Elm code would just not work at all.