Replication addon code cleanup

This is a housekeeping ticket. It removes an unnecessary dependency
on Active Tasks but mostly just contains style fixes, a little JS
rewrite and the odd markup bug fix.
Fix bulkDeleteDocsCollection errors

There are a couple of JS errors that occur when going to and from
the Views page. This just adds a check to confirm a var is really
available before using it.
Nightwatch test for Verify Installation page
Recognize manual URL changes on doc editor page

This ticket lets users manually change the URL on the doc editor page
and have the page automatically load the new doc.

Closes COUCHDB-2490