Game patch images really work now

This means that ALL sprite images should work now. Therefore, Milestone
2 Alpha 1 should be released soon...
Add MidiGuyDP's Newer Background Images

And added him to the readme credits.
Readme changes

Added Atomic Python to translators list, and changed the format for
users with differing usernames and display names.
Moved the SpriteImage_LiquidOrFog class

Small change, no noticeable effect in editor. This is just a cleanup
step I forgot to do earlier.
Few more small changes to sprites.py

Last minor sprites.py changes for now.
Remove a testing thing

Found a print statement I forgot to get rid of before.
Fix auxiliary items; add door stuff

Firstly, all auxiliary items were broken, but now aren't. Next, I added
the door entrance-placement indicator (which required the addition of a
new function in the AuxiliaryItem class). Finally, I added brand-new
images for sprites 319 and 320 (the unused giant doors).
Add a sprite image for Beta Larry

Finally. He gets his own image and doesn't need to borrow that of real
Larry.
Add an image for 257: Move-When-On Metal Lava Block

This is the one used in retail 8-3. Now it gets its own images.
Small change to reggie.py; fix sprite image bugs

reggie.py change may or may not help. Also fixed a couple of bugs that
caused Lava Iron Block and Moving Gem Block to not load.
Updates for the Coin image

Added coin-in-bubble image, and changed it such that only the normal
coin type (type 0) will use the regular coin sprite image; all others
(except for Frozen Coin and Bubble Coins) will use the Special Coin
image.
Small change to make spritelib more efficient

Now it doesn't need to check ImageCache for every image.