Work on asset synchronization and initialization

modules/sync/syncs/httpsynchronization.h

@@ -35,11 +35,15 @@ namespace openspace {
 class HttpSynchronization : public ResourceSynchronization {
 public:
     HttpSynchronization(const ghoul::Dictionary& dict);
-    bool needsSync() override;
-    void start();
     static documentation::Documentation Documentation();
 };
 
+class HttpSynchronizationJob : public SynchronizationJob {
+    HttpSynchronizationJob(std::shared_ptr<ResourceSynchronization> synchronization);
+    void execute() override;
+};
+
+
 } // namespace openspace
 
 #endif // __OPENSPACE_MODULE_SYNC___HTTPSYNCHRONIZATION___H__