Some quality of life fixes

It has been a long time since we've seen an update but this game has been accepted into the Retro Gaming Expo indie arcade (hosted by the Portland Indie Game Squad, main floor booth 3500)! So I've made some changes to make it a little nicer:

• The game no longer starts immewdiately when mew launch it
• Mew can paws by clicking the mouse button
• Yarn balls will always be visible for a little bit before they can be collected (so the cats don't look like they're just jumping at random)

Maybe before the show I'll finally get around to implementing some other collectible items too! But it's been so long since I've touched the code I don't really remember how most of it works.