#899 pybel can't output copyformat

[cowsandmilk]

pybel reports it can output copyformat, but it seemingly cannot.

In [1]: import pybel

In [2]: pybel.outformats['copy']
Out[2]: 'Copy raw text'

In [3]: mol = pybel.readfile("sdf", "Components-pub_less_than_300MW.sdf.gz").next()

In [4]: mol.write('copy','test.sdf')
Not a valid output format