FacetComponent returns list of alternate name, value instead of map for counts in JSON responses

Facet counts for facet.field come back in JSON format like this (a list of name and values, where even positions are keys and odd positions are values).

"facet_counts":{
"facet_fields":{
"u_idx":[
"section",39663,
"adam",6211,
"image",3840,
"slideshow",2480],
...

unlike facet.query facet counts, which come back like this (a map of name value pairs).

"facet_queries":

Unknown macro: { "u_reviewdate}

,

This is only for wt=json. With wt=xml, the two formats look similar.

<lst name="facet_queries">
<int name="u_reviewdate:[NOW-6MONTH TO NOW]">42</int>
<int name="u_reviewdate:[NOW-1YEAR TO NOW-6MONTHS]">1561</int>
<int name="u_reviewdate:[NOW-2YEAR TO NOW-1YEAR]">3017</int>
<int name="u_reviewdate:[NOW-5YEAR TO NOW-2YEAR]">1538</int>
<int name="u_reviewdate:[NOW-100YEAR TO NOW-5YEAR]">47</int>
</lst>

<lst name="facet_fields">
<lst name="u_idx">
<int name="section">39663</int>
<int name="adam">6211</int>
<int name="image">3840</int>
<int name="slideshow">2480</int>
</lst>

I believe this is because of the use of NamedList for this data structure in FacetCountsComponent, SimpleOrderedMap should be used instead. This will produce results of facet_field counts like a map in JSON format (and keep the XML output the same).

"facet_counts":{
"facet_fields":{
"u_idx":[
"section":39663,
"adam":6211,
"image":3840,
"slideshow":2480],
...

This makes it consistent across different kinds of facets and is easier to consume on the client.

There is the concern about backward compatibility (ie users are already consuming the incorrect/inconsistent format so we can't change it), but if that is not as important as consistency and ease of use, then I can supply a patch for this.