Add integration task

https://jira.webfilings.com/browse/HY-660

## Summary 
Both wf-js-annotations and wf-js-viewer leverage TestDataProvider in their *IntegrationSpecs. The TestDataProvider assumes a dev_appserver backend is provided to load test data; without it `grunt jasmine:test` fails.

## Solution
1) Make two subsets of the spec glob, unitSpecs and integrationSpecs
2) Amend `jasmine:test` and `jasmine:coverage` to run only unitSpecs
3) Introduce `jasmine:integration` to run only integrationSpecs