[PL] Add explicit template instantiation for GWF.

Add a fwd include file, and a explicit template
instantiation definition in own compilation unit.

This decouples ogs.cpp from GWF process.

Applications/ApplicationsLib/ProjectData.h

@@ -25,6 +25,7 @@
 #include "ProcessLib/ProcessVariable.h"
 #include "ProcessLib/Process.h"
 #include "ProcessLib/Parameter.h"
+#include "ProcessLib/GroundwaterFlowProcess-fwd.h"
 
 namespace MeshLib {
 	class Mesh;

ProcessLib/GroundwaterFlowProcess-fwd.h

+/**
+ * \copyright
+ * Copyright (c) 2012-2015, OpenGeoSys Community (http://www.opengeosys.org)
+ *            Distributed under a Modified BSD License.
+ *              See accompanying file LICENSE.txt or
+ *              http://www.opengeosys.org/project/license
+ *
+ */
+
+#ifndef PROCESS_LIB_GROUNDWATERFLOWPROCESS_FWD_H_
+#define PROCESS_LIB_GROUNDWATERFLOWPROCESS_FWD_H_
+
+#include "GroundwaterFlowProcess.h"
+#include "NumericsConfig.h"
+
+extern template class ProcessLib::GroundwaterFlowProcess<GlobalSetupType>;
+
+#endif  // PROCESS_LIB_GROUNDWATERFLOWPROCESS_FWD_H_

ProcessLib/GroundwaterFlowProcess.cpp

+/**
+ * \copyright
+ * Copyright (c) 2012-2015, OpenGeoSys Community (http://www.opengeosys.org)
+ *            Distributed under a Modified BSD License.
+ *              See accompanying file LICENSE.txt or
+ *              http://www.opengeosys.org/project/license
+ *
+ */
+
+#include "GroundwaterFlowProcess-fwd.h"
+#include "GroundwaterFlowProcess.h"
+
+namespace ProcessLib
+{
+
+template class GroundwaterFlowProcess<GlobalSetupType>;
+
+}   // namespace ProcessLib

ProcessLib/Process.h

@@ -42,9 +42,4 @@ protected:
 
 }   // namespace ProcessLib
 
-//
-// Include all known processes here.
-//
-#include "GroundwaterFlowProcess.h"
-
 #endif  // PROCESS_LIB_PROCESS_H_