E2E infrastructure

- Gulp E2E test-related tasks
- Gulp process for Angular template caching
- Sample test app that uses common header
- Get rid of references of shopping card & store API loader
- Dummy authentication scenario test file
- Import GAPI mock from store; remove store-related mocks
Further decoupling from store
- Put system message to its own service
- localStorage variable
- Util service that uses dateIsInRange
- Fix UI router state transition bugs
Authorize & logout E2E tests
Merge pull request #7 from settinghead/master

E2E infrastructure