Rename package to js_of_ocaml

[jordwalke]

It's okay to keep the github repo name as is, but I think the package.json "name" field for precompiled binary packages has to match the non-precompiled version. This will make it possible to use shrinkwrap later, but even before then I believe it causes some issues.

For example, the rebel docs assume that the findlib name of a package is the same as the package.json name.

[jordwalke]

Couldn't we just do what you did for rebel, where we have the same package but with a git tag #bin?