This still isn't right.  The `mochijson2:decode` function will convert all JSON string to binary.  It will convert JSON arrays to a list.  So `L` will always be a list of arbitrary erlang terms.  Which means we should encode it with `term_to_binary`.  The problem is I don't think we have any easy way to make PB search smart enough to know to decode that back with `binary_to_term` on the client side.

This is important because Solr returns a multiValued store field as a JSON array.  I'm not sure how to work around this problem.