Add minimal version of predicate editor copied over from mySTEP.

Source/NSPredicateEditor.m

@@ -0,0 +1,50 @@
+/** <title>NSPredicateEditor</title>
+
+   <abstract>The predicate editor class</abstract>
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   Author: Fred Kiefer <fredkiefer@gmx.de>
+   Date:   January 2020
+
+   This file is part of the GNUstep GUI Library.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; see the file COPYING.LIB.
+   If not, see <http://www.gnu.org/licenses/> or write to the
+   Free Software Foundation, 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.
+*/
+
+#import "AppKit/NSPredicateEditor.h"
+
+
+@implementation NSPredicateEditor
+
+- (void) dealloc
+{
+  RELEASE(_rowTemplates);
+  [super dealloc];
+}
+
+- (NSArray *) rowTemplates
+{
+  return _rowTemplates;
+}
+
+- (void) setRowTemplates: (NSArray *)templates
+{
+  ASSIGN(_rowTemplates, templates);
+}
+
+@end