Switch to tokio from tokio-core

Author: blackbeam

Cargo.toml

@@ -22,7 +22,7 @@ native-tls = { version = "0.2", optional = true }
 regex = "1"
 serde = "1"
 serde_json = "1"
-tokio-core = "0.1"
+tokio = "0.1"
 tokio-io = "0.1"
 twox-hash = "1"
 url = "1"