feat(clippy): Use clippy for it's extra lints

serde_macros/Cargo.toml

@@ -13,6 +13,7 @@ name = "serde_macros"
 plugin = true
 
 [dependencies]
+clippy = "^0.0.35"
 serde_codegen = { version = "*", path = "../serde_codegen", default-features = false, features = ["nightly"] }
 
 [dev-dependencies]

serde_macros/benches/bench.rs

@@ -1,4 +1,5 @@
 #![feature(custom_attribute, custom_derive, plugin, test)]
+#![plugin(clippy)]
 #![plugin(serde_macros)]
 
 extern crate num;

serde_macros/src/lib.rs

@@ -1,4 +1,5 @@
-#![feature(plugin_registrar, rustc_private)]
+#![feature(plugin, plugin_registrar, rustc_private)]
+#![plugin(clippy)]
 
 extern crate serde_codegen;
 extern crate rustc_plugin;