Remove return values from initialize and deinitialize functions

src/rendering/renderable.cpp

@@ -139,6 +139,10 @@ Renderable::Renderable(const ghoul::Dictionary& dictionary)
 
 Renderable::~Renderable() {}
 
+void Renderable::initialize() {}
+
+void Renderable::deinitialize() {}
+
 void Renderable::setBoundingSphere(float boundingSphere) {
     _boundingSphere = boundingSphere;
 }