Improve audiorecorder example.

- Possibility to select channel count
- Show audio level for unsigned integer samples
- Show audio level for each channel
- Correctly set output file location
- Update controls depending on the recorder status (rather than the state)

Change-Id: Ieb08c379bb01a11ce1aa52a9d92ea1f320c87d49
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

examples/multimedia/audiorecorder/qaudiolevel.cpp

@@ -45,6 +45,8 @@ QAudioLevel::QAudioLevel(QWidget *parent)
   : QWidget(parent)
   , m_level(0.0)
 {
+    setMinimumHeight(15);
+    setMaximumHeight(50);
 }
 
 void QAudioLevel::setLevel(qreal level)