Should we change this message to say ``See http://qiime.org/install/install.html for currently supported version(s).`` to avoid constant issues with having to remember what this is. Alternatively, we can add a function in ``qiime.util`` called ``get_supported_usearch_version`` which gets called here and in ``print_qiime_config.py``. 

Actually, scratch this for now, but I'm going to add an issue.