Remove clang warnings

Update SGCT repository

src/engine/downloadmanager.cpp

@@ -51,10 +51,6 @@
 namespace {
     constexpr const char* _loggerCat = "DownloadManager";
 
-    constexpr const char* RequestIdentifier = "identifier";
-    constexpr const char* RequestFileVersion = "file_version";
-    constexpr const char* RequestApplicationVersion = "application_version";
-
     struct ProgressInformation {
         std::shared_ptr<openspace::DownloadManager::FileFuture> future;
         std::chrono::system_clock::time_point startTime;

src/engine/openspaceengine.cpp

@@ -111,11 +111,9 @@ namespace {
     constexpr const char* SgctConfigArgumentCommand = "-config";
 
     constexpr const int CacheVersion = 1;
-    constexpr const int DownloadVersion = 1;
 
     const glm::ivec3 FontAtlasSize{ 1536, 1536, 1 };
 
-
     struct {
         std::string configurationName;
         std::string sgctConfigurationName;
@@ -707,7 +705,7 @@ void OpenSpaceEngine::loadSingleAsset(const std::string& assetPath) {
             }
         }
     }
-    _loadingScreen->setItemNumber(resourceSyncs.size());
+    _loadingScreen->setItemNumber(static_cast<int>(resourceSyncs.size()));
 
     bool loading = true;
     while (loading) {

src/engine/settingsengine.cpp

@@ -73,7 +73,7 @@ void SettingsEngine::initialize() {
 
     // Set interaction to change ConfigurationManager and schedule the load
     _scenes.onChange([this, nScenes, sceneDir]() {
-        if (_scenes == nScenes) {
+        if (_scenes == static_cast<int>(nScenes)) {
             OsEng.scheduleLoadSingleAsset("");
         } else {
             std::string sceneFile = _scenes.getDescriptionByValue(_scenes);