Add kra and ora imageio plugins (read-only)

kra is the native format for Krita and ora the interchange format
for krita, gimp and mypaint (it's also mypaint's native format).
Both formats are simply zip containers with an embedded png.

REVIEW:126675

src/imageformats/ora.h

@@ -0,0 +1,38 @@
+/* This file is part of the KDE project
+   Copyright (c) 2013 Boudewijn Rempt <boud@valdyas.org>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the Lesser GNU General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+*/
+
+#ifndef KIMG_ORA_H
+#define KIMG_ORA_H
+
+#include <QImageIOPlugin>
+
+class OraHandler : public QImageIOHandler
+{
+public:
+    OraHandler();
+
+    bool canRead() const Q_DECL_OVERRIDE;
+    bool read(QImage *image)  Q_DECL_OVERRIDE;
+
+    static bool canRead(QIODevice *device);
+};
+
+
+class OraPlugin : public QImageIOPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "ora.json")
+public:
+    Capabilities capabilities(QIODevice *device, const QByteArray &format) const Q_DECL_OVERRIDE;
+    QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const Q_DECL_OVERRIDE;
+};
+
+
+#endif
+