Address clang tidy complaints

Update Ghoul repository
Update SGCT repository

modules/cefwebgui/cefwebguimodule.cpp

@@ -139,11 +139,11 @@ void CefWebGuiModule::internalInitialize(const ghoul::Dictionary& configuration)
     _visible = configuration.hasValue<bool>(VisibleInfo.identifier) &&
                configuration.value<bool>(VisibleInfo.identifier);
 
-    global::callback::initializeGL.push_back([this]() {
+    global::callback::initializeGL.emplace_back([this]() {
         startOrStopGui();
     });
 
-    global::callback::draw2D.push_back([this](){
+    global::callback::draw2D.emplace_back([this](){
         const bool isGuiWindow =
             global::windowDelegate.hasGuiWindow() ?
             global::windowDelegate.isGuiWindow() :
@@ -160,7 +160,7 @@ void CefWebGuiModule::internalInitialize(const ghoul::Dictionary& configuration)
         }
     });
 
-    global::callback::deinitializeGL.push_back([this]() {
+    global::callback::deinitializeGL.emplace_back([this]() {
         _enabled = false;
         startOrStopGui();
     });

modules/cefwebgui/src/guikeyboardhandler.cpp

@@ -31,7 +31,7 @@ namespace openspace {
 GUIKeyboardHandler::GUIKeyboardHandler() {
     _keyConsumed = false;
 
-    global::callback::keyboard.push_back(
+    global::callback::keyboard.emplace_back(
         [&](Key, KeyModifier, KeyAction) -> bool {
             const bool previous = _keyConsumed;
             _keyConsumed = false;

modules/cefwebgui/src/guirenderhandler.cpp

@@ -57,7 +57,7 @@ GUIRenderHandler::GUIRenderHandler() {
     glBindBuffer(GL_ARRAY_BUFFER, _vbo);
     glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW);
     glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), 0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), nullptr);
     glBindVertexArray(0);
     LDEBUG("Initializing CEF GL environment... done!");
 }