Re-export actix dependency. Closes #260 (#264)

- Re-export actix's prelude into actix namespace
- Removing implicit dependency on root's actix module

src/lib.rs

@@ -132,7 +132,7 @@ extern crate serde_json;
 extern crate serde_urlencoded;
 extern crate smallvec;
 #[macro_use]
-extern crate actix;
+pub extern crate actix as actix_inner;
 
 #[cfg(test)]
 #[macro_use]
@@ -195,6 +195,12 @@ pub use httpresponse::HttpResponse;
 pub use json::Json;
 pub use scope::Scope;
 
+pub mod actix {
+    //! Re-exports [actix's](https://docs.rs/actix) prelude
+
+    pub use actix_inner::prelude::*;
+}
+
 #[doc(hidden)]
 #[deprecated(since = "0.6.2", note = "please use `use actix_web::ws::WsWriter`")]
 pub use ws::WsWriter;