Streamline typeahead for stream links.

We don't need to get sorted streams in the "source"
function for typeahead, since we sort them later,
and we don't need to recalculate values.

This preserves the behavior that we include
unsubscribed streams in the typeahead, which is
probably intentional.

static/js/composebox_typeahead.js

@@ -411,7 +411,7 @@ exports.compose_content_begins_typeahead = function (query) {
 
         this.completing = 'stream';
         this.token = current_token;
-        return stream_data.get_streams_for_settings_page();
+        return stream_data.get_unsorted_subs();
     }
     return false;
 };

static/js/stream_data.js

@@ -147,6 +147,10 @@ exports.get_non_default_stream_names = function () {
     return names;
 };
 
+exports.get_unsorted_subs = function () {
+    return stream_info.values();
+};
+
 exports.subscribed_subs = function () {
     return _.where(stream_info.values(), {subscribed: true});
 };