upgrade to native-tls 0.2 + invalid certs (#325)

- Bumps `native-tls` dependency to 0.2 and adapt code accordingly
- Import code used from `tokio-tls` into `connect_async` and adapt dependencies accordinlgy
- Add an option for using `danger_accept_invalid_certs` inside the `Config` struct

src/connect.rs

@@ -6,7 +6,7 @@ use hyper::client::connect::{Connect, Connected, Destination};
 use hyper_tls::{HttpsConnector, MaybeHttpsStream};
 use native_tls::TlsConnector;
 use tokio_io::{AsyncRead, AsyncWrite};
-use tokio_tls::{TlsConnectorExt, TlsStream};
+use connect_async::{TlsConnectorExt, TlsStream};
 
 use std::io::{self, Cursor, Read, Write};
 use std::sync::Arc;
@@ -33,10 +33,6 @@ impl Connector {
             tls: tls,
         }
     }
-
-    pub fn danger_disable_hostname_verification(&mut self) {
-        self.https.danger_disable_hostname_verification(true);
-    }
 }
 
 impl Connect for Connector {