Add support for converting and rendering volumetric data in the cdf format. Replace DataConverter by a more general purpose TaskRunner.

Conflicts:
	modules/volume/CMakeLists.txt
	modules/volume/linearlrucache.h
	src/engine/openspaceengine.cpp

include/openspace/engine/configurationmanager.h

@@ -68,6 +68,8 @@ public:
     static const std::string KeyFactoryDocumentation;
     /// The key that stores the location of the scene file that is initially loaded
     static const std::string KeyConfigScene;
+    /// The key that stores the location of the tasks file that is initially loaded
+    static const std::string KeyConfigTask;
     /// The key that stores the subdirectory containing a list of all startup scripts to
     /// be executed on application start before the scene file is loaded
     static const std::string KeyStartupScript;

include/openspace/util/distanceconstants.h

@@ -0,0 +1,34 @@
+/*****************************************************************************************
+*                                                                                       *
+* OpenSpace                                                                             *
+*                                                                                       *
+* Copyright (c) 2014-2016                                                               *
+*                                                                                       *
+* Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
+* software and associated documentation files (the "Software"), to deal in the Software *
+* without restriction, including without limitation the rights to use, copy, modify,    *
+* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
+* permit persons to whom the Software is furnished to do so, subject to the following   *
+* conditions:                                                                           *
+*                                                                                       *
+* The above copyright notice and this permission notice shall be included in all copies *
+* or substantial portions of the Software.                                              *
+*                                                                                       *
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
+* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
+* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
+* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
+* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
+* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
+****************************************************************************************/
+
+namespace openspace {
+
+namespace distanceconstants {
+	const float EarthRadius = 6371;
+	const float LightYear = 9.4607304725808E15;
+	const float AstronomicalUnit = 1.495978707E11;
+	const float Parsec = 3.0856776E16;
+}
+
+}

include/openspace/util/task.h

@@ -0,0 +1,23 @@
+#ifndef __CONVERSIONTASK_H__
+#define __CONVERSIONTASK_H__
+
+#include <functional>
+#include <ghoul/misc/dictionary.h>
+#include <openspace/documentation/documentation.h>
+
+namespace openspace {
+
+class Task {
+public:
+    using ProgressCallback = std::function<void(float)>;
+
+    virtual ~Task() = default;
+    virtual void perform(const ProgressCallback& onProgress) = 0;
+    virtual std::string description() = 0;
+    static std::unique_ptr<Task> createFromDictionary(const ghoul::Dictionary& dictionary);
+    static openspace::Documentation documentation();
+};
+
+}
+
+#endif

include/openspace/util/taskloader.h

@@ -0,0 +1,17 @@
+#ifndef __TASKRUNNER_H__
+#define __TASKRUNNER_H__
+
+#include <string>
+#include <ghoul/misc/dictionary.h>
+#include <openspace/util/task.h>
+
+namespace openspace {
+class TaskLoader {
+public:
+    std::vector<std::unique_ptr<Task>> tasksFromDictionary(const ghoul::Dictionary& dictionary);
+    std::vector<std::unique_ptr<Task>> tasksFromFile(const std::string& path);
+};
+
+}
+
+#endif