Autocomplete migrated to jquery-ui autocomplete

No longer bundled with the library (as jquery-ui is bundled with the
main software, including the autocomplete part).

Rewrites had to be made to migrate, as several API things had changed
when jquery-ui took over the library.

Currently (like before, right?) this only autocompletes in the end of
the current textarea. So you can't jump back in the middle of a text
and autocomplete a user or group. This is a serious deficiency, though
not a regression.

plugins/Autocomplete/js/autocomplete.go.js

@@ -0,0 +1,71 @@
+/** Init for Autocomplete (requires jquery-ui)
+ *
+ * @package   Plugin
+ * @author Mikael Nordfeldth <mmn@hethane.se>
+ * @copyright 2013 Free Software Foundation, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://status.net/
+ */
+
+var origInit = SN.Init.NoticeFormSetup;
+SN.Init.NoticeFormSetup = function(form) {
+    origInit(form);
+
+    // Only attach to traditional-style forms
+    var textarea = form.find('.notice_data-text:first');
+    if (textarea.length == 0) {
+        return;
+    }
+
+    function termSplit(val) {
+        return val.split(/ \s*/);
+    }
+    function extractLast( term ) {
+        return termSplit(term).pop();
+    }
+    var apiUrl = $('#autocomplete-api').attr('data-url');
+    // migrated "multiple" and "multipleSeparator" from
+    // http://www.learningjquery.com/2010/06/autocomplete-migration-guide
+    textarea
+        .bind('keydown', function( event ) {
+            if ( event.keyCode === $.ui.keyCode.TAB &&
+                $( this ).data( "ui-autocomplete" ).menu.active ) {
+                event.preventDefault();
+            }
+        })
+        .autocomplete({
+            minLength: 1,   // 1 is default
+            source: function (request, response) {
+                $.getJSON( apiUrl, {
+                    term: extractLast(request.term)
+                }, response );
+            },
+            search: function () {
+                // custom minLength, we though we match the 1 below
+                var term = extractLast(this.value);
+                if (term.length <= 1) {
+                    return false;
+                }
+            },
+            focus: function () {
+                // prevent value inserted on focus
+                return false;
+            },
+            select: function (event, ui) {
+                var terms = termSplit(this.value);
+                terms.pop();    // remove latest term
+                terms.push(ui.item.value);  // insert
+                terms.push(''); // empty element, for the join()
+                this.value = terms.join(' ');
+                return false;
+            },
+        })
+        .data('ui-autocomplete')._renderItem = function (ul, item) {
+            return $('<li></li>')
+                .data('ui-autocomplete-item', item)
+                .append('<a><img style="display:inline; vertical-align: middle"><span /></a>')
+                .find('img').attr('src', item.avatar).end()
+                .find('span').text(item.label).end()
+                .appendTo(ul);
+        };
+};