First state on `StateManager` is not hardcoded anymore
Made possible for the GameStates to change from one to another
Removed awful return values from all `GameState::update()` functions
Removed awful arguments and return values from `GameState::load` and `GameState::unload`
`StateManager` is completely intependent of the user game now
Commented a bit on `InputManager`
Commented a bit on `Globals`
Made `StateManager::run` start with the first state
Split `Utils::String` to its own file
Split `Utils::File` to its own file
Split `Utils::Base64` to its own file
Commented on `Color`, `ColorPair` and `Colors`
Commented on `Ncurses`
Removed some useless code
Made Ncurses `WINDOW*` private, on the Window class