Addresses Issue #62.  Test code for metagenome_contributions.py.
Addresses Issue #62.  Adds library code for a method for breaking down the contribution of individual organisms to a metagenome.
Addresses Issue #62.  Initial commit of a script for breaking down the contribution of individual organisms to a metagenome.
Minor tweaks to make sure function limitation is working
Merge pull request #66 from zaneveld/metagenome_contributions

Metagenome contributions