Add moment.js as a dependency
Use moment in the places we are currently doing date things in the toolkit
Change AppTester to only add existing users to the kv store
Fix bad sentence in comment in AppTester's setup tasks
Document in AppTester.setup.user that we assume the user exists if a non-address property is specified
Mention user:new and user:load events in AppTester.setup.user docstring
Merge branch 'feature/issue-158-apptester-assumes-users-always-exist' into develop
Rename pyutc to vumi_utc
Merge branch 'develop' into feature/issue-157-add-moment-js

Conflicts:
	lib/utils.js
Merge branch 'feature/issue-157-add-moment-js' into develop
Merge branch 'develop' into feature/issue-159-user-events-are-fired-before-the-app-is-set-up