Cherrypick remaining changes from the feature/catch2 branch sans the big switch to SGCT 3.0

include/openspace/engine/windowdelegate.h

@@ -96,13 +96,9 @@ struct WindowDelegate {
 
     glm::ivec4 (*viewportPixelCoordinates)() = []() { return glm::ivec4(0, 0, 0, 0); };
 
-    bool (*isExternalControlConnected)() = []() { return false; };
-
     void (*sendMessageToExternalControl)(const std::vector<char>& message) =
         [](const std::vector<char>&) {};
 
-    bool (*isSimpleRendering)() = []() { return true; };
-
     bool (*isFisheyeRendering)() = []() { return false; };
 
     unsigned int(*takeScreenshot)(bool applyWarping) = [](bool) { return 0u; };

include/openspace/scene/assetloader.h

@@ -61,7 +61,7 @@ class AssetListener;
 
 class AssetLoader {
 public:
-    AssetLoader(ghoul::lua::LuaState& luaState, SynchronizationWatcher* syncWatcher,
+    AssetLoader(ghoul::lua::LuaState* luaState, SynchronizationWatcher* syncWatcher,
         std::string assetRootDirectory);
 
     ~AssetLoader();