Partial commit. Simplification of how sequences work in Angular.js client

The view url for an entry is now /course/courseId/view/entryId.
This makes Markdown links between content entries as simple as
[link to entry](entryId)

The lookup url (for topics etc) is now /course/courseId/view/lookup?topic=.
This makes Markdown links for looking up a topic
[link to topic](lookup?topic=my topic)