build: run unit tests sequentially in travis

Author: dpopp07

package.json

@@ -119,7 +119,7 @@
     "test-integration": "mocha test/integration",
     "test-unit": "jest test/unit/",
     "test": "npm run test-unit && npm run test-integration && nyc report --reporter=html",
-    "test-travis": "npm run test-unit && nyc mocha test/integration/ --grep @slow --invert && nyc report --reporter=html",
+    "test-travis": "jest --silent --runInBand test/unit/ && nyc mocha test/integration/ --grep @slow --invert && nyc report --reporter=html",
     "report-coverage": "nyc report --reporter=text-lcov > coverage.lcov && ./node_modules/.bin/codecov",
     "watch-doc": "nodemon --watch ./ --ext js,tmpl,json --ignore dist/ --ignore doc/ --ignore test/ --ignore examples/ --exec npm run doc",
     "watch": "npm run test-unit -- --watch",