Minor `tower` crate re-org (#201)

- Rename `tower::ext` -> `tower::util`.
- Re-export structs from `tower-service-util` in `tower::util`.
- Re-export `tower_service::Service` at root.

tower/src/lib.rs

@@ -7,12 +7,9 @@ extern crate tokio_mock_task;
 extern crate tower_service;
 extern crate tower_service_util;
 
-pub mod ext;
+pub mod util;
 
-pub use ext::ServiceExt;
-pub use tower_service_util::BoxService;
-pub use tower_service_util::EitherService;
+pub use tower_service::Service;
 pub use tower_service_util::MakeConnection;
 pub use tower_service_util::MakeService;
-pub use tower_service_util::OptionService;
-pub use tower_service_util::ServiceFn;
+pub use util::ServiceExt;

tower/src/util/apply.rs

@@ -69,7 +69,7 @@ mod tests {
     use futures::{Async, Future, Poll};
     use tower_service::Service;
 
-    use ext::ServiceExt;
+    use crate::ServiceExt;
 
     #[derive(Clone)]
     struct Srv;

tower/src/util/mod.rs

@@ -22,6 +22,12 @@ pub use self::oneshot::Oneshot;
 pub use self::ready::Ready;
 pub use self::then::Then;
 
+// `tower-service-util` re-exports
+pub use tower_service_util::BoxService;
+pub use tower_service_util::EitherService;
+pub use tower_service_util::OptionService;
+pub use tower_service_util::ServiceFn;
+
 impl<T: ?Sized, Request> ServiceExt<Request> for T where T: Service<Request> {}
 
 type Error = Box<::std::error::Error + Send + Sync>;