Pause menu and checkpoint system update — Thornwood Palace Steam update #1148622

I have had many folks tell me TWP is really hard, and that was never my intention for this game. To be more respectful of players time, I updated the checkpoint system to make the game less monotonous. Also fixed the pause menu (had some players tell me it was easy to accidentally quit to the main menu). Changes - updated the pause menu UI and added music volume control to it - updated the checkpoint system to allow the player to respawn in current room (vs having to start from the beginning of the level) - fixed some other smaller bugs