Restructuring for OpenSpace tests

- Moved all OpenSpace headers to separate include directory
- Added OpenSpaceTests binary with OPENSPACE_HAVE_TESTS define
- Added CMake setting of BASE_DIR
- Added OpenSpace initial tests for SceneGraph and SceneGraphNodes
- Added OpenSpace initial tests for psc and pss
- Restructured OpenSpace so no GL functions are called in constructors
to make the classes testable

- Todo: Make the base dir possible to set through command line argument
and configuration file

include/openspace/interaction/interactionhandler.h

@@ -0,0 +1,78 @@
+#ifndef INTERACTIONHANDLER_H
+#define INTERACTIONHANDLER_H
+
+// open space includes
+#include <openspace/util/camera.h>
+#include <openspace/interaction/externalcontrol/externalcontrol.h>
+#include <openspace/scenegraph/scenegraphnode.h>
+
+// std includes
+#include <vector>
+#include <thread>
+#include <mutex>
+#include <memory>
+
+namespace openspace {
+
+class InteractionHandler {
+public:
+    InteractionHandler(void);
+    InteractionHandler(const InteractionHandler& src);
+    InteractionHandler& operator=(const InteractionHandler& rhs);
+	virtual ~InteractionHandler();
+
+	//static void init();
+	//static void deinit();
+ //   static InteractionHandler& ref();
+	//static bool isInitialized();
+
+	void enable();
+	void disable();
+	const bool isEnabled() const;
+
+	void connectDevices();
+	void addExternalControl(ExternalControl* controller);
+
+	void setCamera(Camera *camera = nullptr);
+	Camera * getCamera() const;
+	const psc getOrigin() const;
+	void lockControls();
+	void unlockControls();
+
+	void setFocusNode(SceneGraphNode *node);
+	
+	void orbit(const glm::quat &rotation);
+	void rotate(const glm::quat &rotation);
+	void distance(const pss &distance);
+
+	void lookAt(const glm::quat &rotation);
+	void setRotation(const glm::quat &rotation);
+
+	void update(const double dt);
+
+	double getDt();
+
+    void keyboardCallback(int key, int action);
+    void mouseButtonCallback(int key, int action);
+    void mousePositionCallback(int x, int y);
+    void mouseScrollWheelCallback(int pos);
+	
+private:
+
+	Camera *camera_;
+	bool enabled_;
+	SceneGraphNode *node_;
+	
+	double dt_;
+
+	// used for calling when updating and deallocation
+	std::vector<ExternalControl*> controllers_;
+
+	// for locking and unlocking
+	std::mutex cameraGuard_;
+	
+};
+
+} // namespace openspace
+
+#endif