Use new JSON parser/generator.

Qt4: Use QJson (http://qjson.sourceforge.net).
Qt5: Use native Qt JSON API.

src/webui/jsonutils.h

@@ -0,0 +1,66 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2014  Vladimir Golovnev
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ *
+ * Contact : glassez@yandex.ru
+ */
+
+#ifndef JSONUTILS_H
+#define JSONUTILS_H
+
+#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+#else
+#include <QString>
+#include "qjson/parser.h"
+#include "qjson/serializer.h"
+#endif
+
+namespace json {
+
+inline QByteArray toJson(const QVariant& var)
+{
+#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
+  return QJsonDocument::fromVariant(var).toJson();
+#else
+  return QJson::Serializer().serialize(var);
+#endif
+}
+
+inline QVariant fromJson(const QString& json)
+{
+#if QT_VERSION >= QT_VERSION_CHECK(5, 0, 0)
+  return QJsonDocument::fromJson(json.toUtf8()).toVariant();
+#else
+  return QJson::Parser().parse(json.toUtf8());
+#endif
+}
+
+}
+
+#endif // JSONUTILS_H