npm test fixes (#72)

* add test:objc to npm test script
* test:coverage separated from npm test script to npm cover script
* separate npm run cover step in .travis.yml

(more consistent with cordova-ios)
diff --git a/.travis.yml b/.travis.yml
index 09f5ab7..97c8f16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,3 +19,4 @@
   - node --version
   - npm --version
   - npm test
+  - npm run cover
diff --git a/package.json b/package.json
index a688885..361247b 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,8 @@
     "cordova:platform"
   ],
   "scripts": {
-    "test": "npm run eslint && npm run test:coverage",
+    "cover": "npm run test:coverage",
+    "test": "npm run eslint && npm run test:component && npm run test:objc",
     "test:objc": "jasmine  --config=tests/spec/objc.json",
     "test:component": "jasmine --config=tests/spec/component.json",
     "test:coverage": "nyc jasmine --config=tests/spec/coverage.json",