Implement new as-based API

[ZacSweers]

This implements a new AutoDispose API (again, but final this time!) around using the new as() operator.

Resolves #140

Other things:

• Moves kotlin to the same name for shared semantics
• Opportunistically updated a few dependencies

Now, the API is just

Observable.just(1)
    .as(autoDisposable(scope))
    .subscribe();

Or in Kotlin

Observable.just(1)
    .autoDisposable(scope)
    .subscribe();

[ZacSweers]

Note the RestrictTo error-prone check is disabled for now because it's totally broken (it thinks only the support library is allowed to use it)