Standardize option longnames on underscores

Fix #1786
Update changelog with dash to underscore changes

Conflicts:
	ChangeLog.md
Remove option-label entry from script_info

Was used by n3phele, not needed any more
Merge branch 'master' of https://github.com/biocore/qiime into dashes_to_underscores-issue-1786

Conflicts:
	ChangeLog.md
	scripts/denoiser.py
Merge branch 'master' of https://github.com/biocore/qiime into dashes_to_underscores-issue-1786
Fix typo
Merge branch 'master' of https://github.com/biocore/qiime into dashes_to_underscores-issue-1786
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
slight DESeq2.r definition change`
Merge pull request #1792 from adamrp/dashes_to_underscores-issue-1786

Changes dashes in option longnames to underscores
Merge pull request #1800 from gregcaporaso/issue-1798

removes summarize_otu_by_cat.py in favor of collapse_samples.py