321 - adds a preferred tuner option to the channel's source configuration

so that on startup, the application attempts to source the channel from
the preferred tuner.

If the tuner is currently not available, or if the tuner cannot source
the channel, then the next available tuner is selected.

src/main/java/io/github/dsheirer/source/SourceManager.java

@@ -59,6 +59,11 @@ public class SourceManager
         return mTunerManager;
     }
 
+    public TunerModel getTunerModel()
+    {
+        return mTunerModel;
+    }
+
     public Source getSource(SourceConfiguration config, int bandwidth)
         throws SourceException
     {