ENH: first pass at updates to the workflow that uses this
ENH: updated variable name for clarity
MAINT: removed out-dated and un-used parameters
ENH: added --normalize option
ENH/REL: removed summarize_otu_by_cat.py, fixes #1798
MAINT: removed script test data
BUG: fixed issue where collapsing only one a single column didn't function as expected
MAINT: simplified
DOC: updates based on suggestions from @jairideout
ENH: updated so parsing of mapping file to DataFrame happens via QIIME parsers for consistency, thanks for the suggestion @jairideout
Merge pull request #1800 from gregcaporaso/issue-1798

removes summarize_otu_by_cat.py in favor of collapse_samples.py