Debugger: Center location marker in assembly mode.

Task-number: QTCREATORBUG-5409

Change-Id: Ib2056005bdc7f7dbaf75c55da73ba0c11ade7c42
Reviewed-on: http://codereview.qt.nokia.com/1540
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/plugins/debugger/disassembleragent.cpp

@@ -340,6 +340,7 @@ void DisassemblerAgent::updateLocationMarker()
     QTextBlock block = tc.document()->findBlockByNumber(lineNumber - 1);
     tc.setPosition(block.position());
     plainTextEdit->setTextCursor(tc);
+    plainTextEdit->centerCursor();
 }
 
 void DisassemblerAgent::updateBreakpointMarkers()