Add contextual help directive

- fetches help given a confluence ID
- preliminary design prototype for contextual help
- build css
- add spinner to initial load
- remove test help from profiler navbar
Merge pull request #508 from strongloop/feature/contextual-help-popover

Add contextual help directive

- fetches help given a confluence ID
- preliminary design prototype for contextual help
- build css
- add spinner to initial load
- remove test help from profiler navbar

fix #672