DirectShow: Refactor camera backend.

Almost entire rewrite of the camera backend. It doesn't provide new
features but is more stable and behave as it should.

- Correctly report camera state and status
- Correctly report if the camera is ready to capture
- Emit imageExposed() signal
- Save captured images in an appropriate directory
- Images can be captured even without a viewport
- Better error handling

Removed the custom QVideoWidgetControl as it doesn't provide anything more
than the QVideoWidget's renderer control fallback.

Task-number: QTBUG-33782
Change-Id: I9baf6f83e7c69619f20a101921f7865a1c90d5e4
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

src/plugins/directshow/player/directshowplayerservice.cpp

@@ -111,7 +111,6 @@ DirectShowPlayerService::DirectShowPlayerService(QObject *parent)
     , m_seekable(false)
     , m_atEnd(false)
 {
-    CoInitialize(NULL);
     m_playerControl = new DirectShowPlayerControl(this);
     m_metaDataControl = new DirectShowMetaDataControl(this);
     m_audioEndpointControl = new DirectShowAudioEndpointControl(this);
@@ -153,7 +152,6 @@ DirectShowPlayerService::~DirectShowPlayerService()
 #endif
 
     ::CloseHandle(m_taskHandle);
-    CoUninitialize();
 }
 
 QMediaControl *DirectShowPlayerService::requestControl(const char *name)