Update & Optimize CI configs

- Test on Node 8
- Only run unit tests on Appveyor
- Optimize TravisCI builds to use the minimum number of containers
  while keeping the performance reasonable

.travis.yml

@@ -1,16 +1,18 @@
 sudo: false
 language: node_js
-node_js:
-  - "4"
-  - "5"
-  - "6"
-  - "7"
 matrix:
   include:
+    - node_js: "4"
+    - node_js: "5"
+    # We run both lint and unit on Node 6
+    - node_js: "6"
+      env: TEST_SUITE=test
     - node_js: "7"
-      env: TEST_SUITE=lint
+    # We run coverage on Node 8
+    - node_js: "8"
+      env: TEST_SUITE=coverage
 env:
   - TEST_SUITE=unit
 script: npm run-script $TEST_SUITE
 after_success:
-  - if [ $TEST_SUITE = lint ]; then npm run coveralls; fi
+  - if [ $TEST_SUITE = coverage ]; then npm run coveralls; fi

appveyor.yml

@@ -4,6 +4,7 @@ environment:
     # node.js
     - nodejs_version: "4"
     - nodejs_version: "6"
+    - nodejs_version: "8"
 
 # Install scripts. (runs after repo cloning)
 install:
@@ -18,8 +19,8 @@ test_script:
   # Output useful info for debugging.
   - node --version
   - npm --version
-  # run tests
-  - npm test
+  # run only unit tests; travis does the linting
+  - npm run unit
 
 # Don't actually build.
 build: off

package.json

@@ -55,7 +55,7 @@
   "main": "./lib/index",
   "scripts": {
     "coverage": "istanbul cover -i 'lib/**' -x '**/__tests__/**' test.js",
-    "coveralls": "npm run coverage && coveralls < coverage/lcov.info",
+    "coveralls": "coveralls < coverage/lcov.info",
     "lint": "standard && standard-markdown",
     "test-find": "find ./lib/**/__tests__ -name *.test.js | xargs mocha",
     "test": "npm run lint && npm run unit",