GOCBC-130: Added support for result sorting in FTS.

Change-Id: If67de30c5d55727b251796f884c65c940a10bab9
Reviewed-on: http://review.couchbase.org/70826
Reviewed-by: Mark Nunberg <mark.nunberg@couchbase.com>
Tested-by: Brett Lawson <brett19@gmail.com>

searchquery.go

@@ -35,6 +35,7 @@ type searchQueryData struct {
 	Explain   bool                      `json:"explain,omitempty"`
 	Highlight *searchQueryHighlightData `json:"highlight,omitempty"`
 	Fields    []string                  `json:"fields,omitempty"`
+	Sort      []string                  `json:"sort,omitempty"`
 	Facets    map[string]interface{}    `json:"facets,omitempty"`
 	Ctl       *searchQueryCtlData       `json:"ctl,omitempty"`
 }
@@ -80,6 +81,12 @@ func (sq *SearchQuery) Fields(fields ...string) *SearchQuery {
 	return sq
 }
 
+// Sort specifies a sorting order for the results.  Only available in Couchbase Server 4.6+.
+func (sq *SearchQuery) Sort(fields ...string) *SearchQuery {
+	sq.data.Sort = fields
+	return sq
+}
+
 // AddFacet adds a new search facet to include in the results.
 func (sq *SearchQuery) AddFacet(name string, facet interface{}) *SearchQuery {
 	if sq.data.Facets == nil {