Merge branch 'make_bipartite_network.py' of git://github.com/wdwvt1/qiime
Merge branch 'master' of git://github.com/qiime/qiime
Merge branch 'master' of git://github.com/qiime/qiime
Add check where all samples are filtered out

Add a test to the test suite with this case.
Add try except block for --valid_states input

Fixes #779
Merge pull request #917 from ElDeveloper/issue_779

Fixes Issue 779