Intermediary level added in between floors; You can now trade coins for arrow power-up, speed boost, hearts and arrows.

- added an intermediary one room dungeon to the ToNextLevelState
- created Entity "Murk" as an npc  who remains in this GameState to potentially trade for coins
- added textbox and simple dialogue
- the power charged arrow must now be purchased; a speed boost, 10 arrows, and a heart can also be purchased.
- new Sprite art integrated for NPC
- also added a short dying scenario; when hero dies he freezes, spins, & everything flashes (similar to the box2d debug mode)
I like what you've done with this method; the new formula lets us dynamically query for tilesets.