auto-include instances in <entry>

include all instances that are referenced
from an xpath within the referenced `<detail>`s

Rather than trying to keep track of which types of case list columns add instance references and adding them using separate but parallel code while generating the `Entry` that references a `Detail`, any instance that shows up in any `Detail` that an `Entry` references now gets added to the `Entry` automatically.

Part of http://manage.dimagi.com/default.asp?117591.