Some fixes in wolves implementation

1. WorldStorage now saves and restores collar's color.
2. If wolf's owner is flying, wolf will be teleported to the nearest non-air block. If owner is located on 30 blocks above wolf, and moving in x-z, wolf will be constantly teleported under his owner (it looks like wolf is flying).
3. Monster's minimal speed is set to 5. I think it is closer to original Minecraft implementation.