Sprite Update: Oct14

All sprites have been put in xy folder to reduce clutter.

Ideally replace the xy files entirely, do not merge there are some extra files that are not necessary such as:

Froakie.png in front/back (should be in lower)
gyrados-mega.png in front/back (misspelling)
tree.gif in afront/aback (not real name)

If a merge is the only option those extra files should be deleted.
Merge pull request #31 from smogon/fix-sprite-update-oct14

Sprite Update: Oct14