constrain default order on models #423

This attempts to partially resolve issues surrounding default ordering
on models. Order has been removed from associations where the order
has already been specified on the target model. In all other cases the
ordering has been scoped to the table. This should not modify the
order specified to any queries.

This allows cases, etc. to perform joins without
explicitly removing order constraints. Possible performance overheads
associated with unnecessary sorting are still an issue. Also, model
class names have been hardcoded to scope associations. I am not sure
how to get around this.

The goal is to allow cases to use mainline surveyor releases.
Pull new render methods into show action:
- Group text translations (#420)
- Answer help text (#373)
- Show labels
Closes #438, closes #442. Thanks @alanjcfs.
Merge branch '423_constrain_default_ordering'.

* 423_constrain_default_ordering:
  constrain default order on models #423