Fix flickering text effect in Title Screen
Improve the Resource Manager interface

Remove ResourceData, ResourceHandler and ResourceHolder.
Use IResourceHolder and TResourceHolder instead, and a map of string unique_ptr<Resource> pairs.
Removed the loading later mechanic. Thus removing the addition of resources.
No need to get a holder first and then call function on it, the more intuitive way now is to use
tempalte member function inside ResourceManager, e.g. manager.load<sf::Texture>("path/to/image.png");
Remove the handlePlayerInput() member function from the Application class
Add Component class
Add Container class
Add Label class
Add Label class
Add comments for spacing
Add SettingsState class and some button textures
Use the filename instead of the resource id when throwing the runtime error
Fix code flow, never called the callback
Fixed typo, change KeyReleased to KeyPressed, and add implementation for draw()
Add navigation buttons to the MenuState
Removed primitive close assigned to the Esc key
Add key binding functionality to the settings state