ENH: removed check of valid sequence characters, fixes #717
BUG: clustal sniffer now returns False on empty file; fixes #716
ENH: skbio.io.read and skbio.io.write are now available as skbio.read and skbio.write; fixes #714
DOC: shortened imports in docs
Merge pull request #720 from gregcaporaso/its-quick-fix-time

quick fixes fixed quickly for  0.2.1