prototyping
Implement simple tabular layout for activity feed. #1594.
Implement trip_ticket#audits_with_associated, to pull in location change audits. #1594.
Generalize rendering of audit trail partials.

Now you just pass in any list of audits, and it does not
necessarily call the "audit" method on objects.

We needed this so we could use "audits_with_associated" on TT
objects.
Don't show empty change line items on non-AJAX audit trail.
In AJAX audit trail, show type of object that was updated. #1594.
Merge branch 'master' into 1594-add-ticket-modified-to-the-activities-feed