Feature/globals (#690)

* Move global objects out of OpenSpaceEngine
 * General cleanup of main.cpp
 * Add default_joystick asset to all scenes
 * No longer suppress mouse interaction on slave nodes
 * Window delegate uses function pointers rather than subclassing
 * Fix for false overwriting of ImGUI configuration file
 * Change default color and tilt angle of fisheye rendering
 * Restructured performance manager
 * Simplify screenshot handling

apps/Sync/main.cpp

@@ -24,8 +24,10 @@
 
 #include <openspace/engine/openspaceengine.h>
 #include <openspace/engine/moduleengine.h>
-#include <openspace/engine/wrapper/windowwrapper.h>
+#include <openspace/engine/windowdelegate.h>
+#include <openspace/engine/configuration.h>
 #include <openspace/util/factorymanager.h>
+#include <openspace/engine/globals.h>
 #include <openspace/util/progressbar.h>
 #include <openspace/util/resourcesynchronization.h>
 #include <openspace/util/task.h>
@@ -40,9 +42,12 @@
 int main(int argc, char** argv) {
     using namespace openspace;
 
-    std::vector<std::string> unusedStringlist;
-    bool unusedBool;
-    OpenSpaceEngine::create(argc, argv, nullptr, unusedStringlist, unusedBool);
+    ghoul::initialize();
+
+    std::string configFile = configuration::findConfiguration();
+    global::configuration = configuration::loadConfigurationFromFile(configFile);
+    global::openSpaceEngine.initialize();
+
 
     TaskLoader taskLoader;
     std::vector<std::unique_ptr<Task>> tasks = taskLoader.tasksFromFile(