Add sndio support

Index: src/core/include/hydrogen/Preferences.h
--- src/core/include/hydrogen/Preferences.h.orig
+++ src/core/include/hydrogen/Preferences.h
@@ -262,6 +262,9 @@ class Preferences : public H2Core::Object (public)
 	//	OSS driver properties ___
 	QString				m_sOSSDevice;		///< Device used for output
 
+	//	SNDIO driver properties ___
+	QString				m_sSndioDevice;		///< Device used for output
+
 	//	MIDI Driver properties
 	/**
 	 * MIDI driver
