Minor alteration to util.py error output
Merge branch 'master' of https://github.com/picrust/picrust
Addresses Issue 70: Fixes descrepencies between tree and trait table based on quoted node names
Addresses Issue #70 Test code for fix to assign_traits_to_tree
Merge pull request #74 from zaneveld/issue_70_quoted_node_names

Issue 70 quoted node names produce an error in predict_traits.py