Backported changes to rdp_classifier.py in PyCogent
Add is_valid_git_refname and is_valid_git_sha1

Given the great variability that exists between versions of git, this
functions validate the output returned from the git commands used to
retrieve the current branch name (refname) and the current SHA.

The function get_qiime_library_version was updated to make use of these
functions.

The module was updated accordingly.

This should fix issue #603.
Modified the compare_alpha_diversity library, script, and tests to resolve issue #597.
Backported changes to rdp_classifier.py in PyCogent
Merge branch 'backport-rdp-classifier' of github.com:kylebittinger/qiime into backport-rdp-classifier
Backported PyCogent commit fec2a29
Merge pull request #606 from kylebittinger/backport-rdp-classifier

Backported changes to rdp_classifier.py in PyCogent
Merge pull request #612 from wdwvt1/compare_alpha_diversity_fixes

Modified the compare_alpha_diversity library, script, and tests to resol...
Merge pull request #609 from ElDeveloper/git_version

Add is_valid_git_refname and is_valid_git_sha1