Cleanup: lower-case filenames in core/subsurface-qt/

We tend to use lower-case filenames. Let's do it for these files
as well. Simple search & replace.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/subsurface-qt/cylinderobjecthelper.cpp

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
-#include "CylinderObjectHelper.h"
+#include "cylinderobjecthelper.h"
 #include "../qthelper.h"
 
 static QString EMPTY_CYLINDER_STRING = QStringLiteral("");

core/subsurface-qt/divelistnotifier.cpp

@@ -1,4 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0
-#include "DiveListNotifier.h"
+#include "divelistnotifier.h"
 
 DiveListNotifier diveListNotifier;

core/subsurface-qt/diveobjecthelper.cpp

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
-#include "DiveObjectHelper.h"
+#include "diveobjecthelper.h"
 
 #include <QDateTime>
 #include <QTextDocument>

core/subsurface-qt/diveobjecthelper.h

@@ -2,7 +2,7 @@
 #ifndef DIVE_QOBJECT_H
 #define DIVE_QOBJECT_H
 
-#include "CylinderObjectHelper.h"
+#include "cylinderobjecthelper.h"
 #include <QObject>
 #include <QString>
 #include <QStringList>