Update version to 0.0.0-dev

Addresses #16
Merge pull request #17 from mlangill/issue16

Update version to 0.0.0-dev
added all_tests.py to faciliate running all tests with one command

this was modified from the version in biom-format.
Merge pull request #22 from picrust/add-all-tests

added all_tests.py to faciliate running all tests with one command
adding setup.py script

addresses issue #20.
Merge pull request #23 from gregcaporaso/add-setup

adding setup.py script