Build stdweb feature on nightly only

Signed-off-by: Robert Vojta <rvojta@me.com>

.travis.yml

@@ -11,19 +11,37 @@ matrix:
   - rust: nightly
     before_script:
     - rustup component add rustfmt-preview
+    - rustup target add wasm32-unknown-unknown
     script:
     - cargo fmt --all -- --check
     - cargo test --features "serde std v1 v3 v4 v5"
     - cargo bench --features "serde std v1 v3 v4 v5"
+    - cargo build --target wasm32-unknown-unknown --features "v3 stdweb"
+    - cargo build --target wasm32-unknown-unknown --features "v4 stdweb"
+    - cargo build --target wasm32-unknown-unknown --features "v5 stdweb"
+    - cargo build --target wasm32-unknown-unknown --features "v3 wasm-bindgen"
+    - cargo build --target wasm32-unknown-unknown --features "v4 wasm-bindgen"
+    - cargo build --target wasm32-unknown-unknown --features "v5 wasm-bindgen"
   - os: linux
     rust: nightly
     script:
     - cargo test --features "const_fn"
+  - rust: beta
+    before_script:
+      - rustup target add wasm32-unknown-unknown
+    script:
+      - cargo build --target wasm32-unknown-unknown --features "v3 wasm-bindgen"
+      - cargo build --target wasm32-unknown-unknown --features "v4 wasm-bindgen"
+      - cargo build --target wasm32-unknown-unknown --features "v5 wasm-bindgen"
   - rust: stable
     before_script:
     - rustup component add clippy-preview
+    - rustup target add wasm32-unknown-unknown
     script:
     - cargo clippy --features "u128 v1 v3 v4 v5 slog"
+    - cargo build --target wasm32-unknown-unknown --features "v3 wasm-bindgen"
+    - cargo build --target wasm32-unknown-unknown --features "v4 wasm-bindgen"
+    - cargo build --target wasm32-unknown-unknown --features "v5 wasm-bindgen"
   - rust: 1.22.0
     script:
     - cargo test --features "serde std v4"
@@ -39,9 +57,6 @@ rust:
 - beta
 - nightly
 
-before_script:
-  - rustup target add wasm32-unknown-unknown
-
 script:
 - cargo test --no-default-features
 - cargo test
@@ -52,11 +67,5 @@ script:
 - cargo test --features "v5"
 - cargo test --features "slog"
 - cargo test --features "serde std v1 v3 v4 v5"
-- cargo build --target wasm32-unknown-unknown --features "v3 stdweb"
-- cargo build --target wasm32-unknown-unknown --features "v3 wasm-bindgen"
-- cargo build --target wasm32-unknown-unknown --features "v4 stdweb"
-- cargo build --target wasm32-unknown-unknown --features "v4 wasm-bindgen"
-- cargo build --target wasm32-unknown-unknown --features "v5 stdweb"
-- cargo build --target wasm32-unknown-unknown --features "v5 wasm-bindgen"
 
 sudo: false