Port towards C++11 nullptr

lib/ScreenWindow.cpp

@@ -30,7 +30,7 @@ using namespace Konsole;
 
 ScreenWindow::ScreenWindow(QObject* parent)
     : QObject(parent)
-    , _windowBuffer(0)
+    , _windowBuffer(nullptr)
     , _windowBufferSize(0)
     , _bufferNeedsUpdate(true)
     , _windowLines(1)
@@ -59,7 +59,7 @@ Character* ScreenWindow::getImage()
 {
     // reallocate internal buffer if the window size has changed
     int size = windowLines() * windowColumns();
-    if (_windowBuffer == 0 || _windowBufferSize != size)
+    if (_windowBuffer == nullptr || _windowBufferSize != size)
     {
         delete[] _windowBuffer;
         _windowBufferSize = size;