Format values in array comparisons as well
Handle searching using Resources as values

Handle DataMapper::Resource values by getting their key value and using
that as value.
Handle associations both ways

Chack if we are the parent or the child to determine which property to
query on.
Sent the limit parameter to puppetdb

Currently only the events endpoint handles it server side, it is
ignored on the other ones. But we filter it again client side anyway so
we can safely send it in case the server can handle it.