Separate drone steps and add clippy

.drone.yml

@@ -13,14 +13,32 @@ steps:
     mount:
       - ./target
 
+- name: build
+  image: rust:1
+  volumes:
+  - name: cargo-registry
+    path: /usr/local/cargo/registry
+  commands:
+  - cargo build --verbose
+
 - name: test
   image: rust:1
   volumes:
   - name: cargo-registry
     path: /usr/local/cargo/registry
   commands:
-  - cargo build --verbose --all
-  - cargo test --verbose --all
+  - cargo test --verbose
+
+- name: clippy
+  image: rust:1
+  failure: ignore
+  volumes:
+  - name: cargo-registry
+    path: /usr/local/cargo/registry
+  commands:
+  - rustup component add clippy
+  - cargo clean -p sprinklers_rs
+  - cargo clippy --all-targets --all-features -- -D warnings
 
 - name: rebuild-target-cache
   image: drillster/drone-volume-cache