Update version strings to 0.2.0
DOC: updated pre-alpha to alpha
Merge pull request #602 from ebolyen/master

DOC: updated pre-alpha to alpha
Merge pull request #601 from jairideout/0.2.0-version-updates

Update version strings to 0.2.0
Update version strings to 0.2.0-dev
Merge pull request #603 from jairideout/0.2.0-dev-version-update

Update version strings to 0.2.0-dev
Merge branch 'master' of https://github.com/biocore/scikit-bio into parse_qseq
More unit tests.