Update, GUI Graphics and More!

I've added a new GUI graphics sheet and also made a few updates to the tilesets.

• Completely overhauled the palm trees. They should match the others much better now.
• Made a really minor clean-up change to the gourd trees (You probably won't even notice).
• Changed the swamp vines a little bit, also included a new spikey variety
• A few statues (The overworld could do with more decorative objects).
• Added grass and leaves effect sprites.
• Also added  map, compass, key, and boss key sprites.