Added source files for OpalLink class

src/comm/OpalLink.cc

+#include "OpalLink.h"
+
+OpalLink::OpalLink()
+{
+}

src/comm/OpalLink.h

+#ifndef OPALLINK_H
+#define OPALLINK_H
+
+class OpalLink : public LinkInterface
+{
+public:
+    OpalLink();
+};
+
+#endif // OPALLINK_H