Do not use deprecated Qt functionality.

Replace all* remaining deprecated Qt 4 functions with
their Qt 5 counterparts. This means we no longer need to
define the QT_DISABLE_DEPRECATED_BEFORE macro.
This patch is relatively small because most source-compatible
changes of this kind have been done before.

* The one exception is the QmlDesigner, which uses QWeakPointer
in a deprecated way all over the place.

Change-Id: Id4b839c6685f3b5bdf2b89137f95231758ec53c7
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cppeditor/cpphoverhandler.cpp

@@ -99,7 +99,7 @@ void CppHoverHandler::identifyMatch(TextEditor::BaseTextEditor *editor, int pos)
 void CppHoverHandler::decorateToolTip()
 {
     if (Qt::mightBeRichText(toolTip()))
-        setToolTip(Qt::escape(toolTip()));
+        setToolTip(toolTip().toHtmlEscaped());
 
     if (isDiagnosticTooltip())
         return;