Use recommended rxjs import form

[ddohler]

Importing 'rxjs/Rx' or 'rxjs' is not recommended. We should switch all imports to use the recommended form, which is import { Observable } from 'rxjs/Observable ';.

[ddohler]

Doing this may cause problems in the Lab and Temperate; the improper imports in this project seem to be enabling functionality that wouldn't otherwise work in those projects. That's not a blocker, but all three will need to be tested.