hyperion won't fail, if v4l2 has invalid device + auto device (#118)

* hyperion won't fail, if v4l2 has invalid device

* add v4l auto select. use "auto" as device name

include/grabber/V4L2Grabber.h

@@ -3,6 +3,7 @@
 // stl includes
 #include <string>
 #include <vector>
+#include <map>
 
 // Qt includes
 #include <QObject>
@@ -50,7 +51,7 @@ public slots:
 					double blueSignalThreshold,
 					int noSignalCounterThreshold);
 
-	void start();
+	bool start();
 
 	void stop();
 
@@ -61,6 +62,11 @@ private slots:
 	int read_frame();
 
 private:
+	void getV4Ldevices();
+	
+	bool init();
+	void uninit();
+
 	void open_device();
 
 	void close_device();
@@ -102,8 +108,11 @@ private:
 	};
 
 private:
-	const std::string _deviceName;
-	const io_method _ioMethod;
+	std::string _deviceName;
+	std::map<std::string,std::string> _v4lDevices;
+	int _input;
+	VideoStandard _videoStandard;
+	io_method _ioMethod;
 	int _fileDescriptor;
 	std::vector<buffer> _buffers;
 
@@ -125,4 +134,5 @@ private:
 	ImageResampler _imageResampler;
 	
 	Logger * _log;
+	bool _initialized;
 };

include/grabber/V4L2Wrapper.h

@@ -30,7 +30,7 @@ public:
 	virtual ~V4L2Wrapper();
 
 public slots:
-	void start();
+	bool start();
 
 	void stop();