Credits and some fixes

I added a credits page in game since I forgot to make one while I was working on the game (oops). Anyway check out Traffic_Butterfly who created the design for Duckbert himself!

Other changes to the game:

-Springs now prevent you from walking while they bounce you so you should rarely have to worry about walking off them

-Some platforms throughout the game have been slowed down since some levels were a bit harder than I would have like to have made them *cough* *cough* 2-3 *cough* *cough* .

-Logo has been altered