Fixed atom ordering for special setups

I can't figure out why git thinks all of my files are different than the ones on your branch.

Only jasp.py and metadata.py have any changes. From jasp.py I removed the get_special_setups function. This feature has been replaced with the storage of special features in the METADATA file. Both types of special setups are now preserved between runs. i.e. setups={'Cu': '_pv'} or setups={'0': 'Cu'}.