domenic/pubit is now NobleJS/pubit-as-promised

With proper license.
Changed README.md to mention promise returned by `publish.when`.
Example voting system given in readme.
`once` is now a synonym for `onNext`.
Change require in the original tests to `require("..")`.
New test for `publish.when()` both sync and async.
Added `publish.when` and maintained backward compatibility with pubit.

`publish.when` now ignores the `async` flag.