Rename headers to end with _p.h

Frameworks have a convention of naming uninstalled headers in src/ with
a _p at the end of the name, to make it clear they are not part of the
API. None of the headers in KImageFormats are installed, so it is not
really necessary to follow this convention, but we follow it anyway for
the benefit of both humans and tools (like kapidox).

src/imageformats/exr_p.h

@@ -0,0 +1,37 @@
+/*
+* QImageIO Routines to read (and perhaps in the future, write) images
+* in the high definition EXR format.
+*
+* Copyright (c) 2003, Brad Hards <bradh@frogmouth.net>
+*
+* This library is distributed under the conditions of the GNU LGPL.
+*
+*/
+
+#ifndef KIMG_EXR_H
+#define KIMG_EXR_H
+
+#include <QImageIOPlugin>
+
+class EXRHandler : public QImageIOHandler
+{
+public:
+    EXRHandler();
+
+    virtual bool canRead() const;
+    virtual bool read(QImage *outImage);
+
+    static bool canRead(QIODevice *device);
+};
+
+class EXRPlugin : public QImageIOPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface" FILE "exr.json")
+
+public:
+    virtual Capabilities capabilities(QIODevice *device, const QByteArray &format) const;
+    virtual QImageIOHandler *create(QIODevice *device, const QByteArray &format = QByteArray()) const;
+};
+
+#endif // KIMG_EXR_H