Removes unused methods and associations from models, and removes the
PageViewRange model completely, which is no longer used.
test plan:
* run the specs
* verify that no active page-view-related functionality was inadvertently removed
Change-Id: I8522d151555db64a0ad2548334ae642f9fefd54e
Reviewed-on: https://gerrit.instructure.com/9324
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Brian Palmer