test: update Travis config to manually spell out the main test command + add a travis_wait to troubleshoot tests timing out

Author: sghoweri

.travis.yml

@@ -16,6 +16,8 @@ before_script:
   - lerna add @pattern-lab/engine-twig --scope=@pattern-lab/core
   - lerna add @pattern-lab/engine-react --scope=@pattern-lab/core
 
+script: travis_wait npm run test
+
 branches:
   only:
     - master