Merge branch 'master' into model-wrappers
unfinished example of wrapper for DESeq2
1.7.3 Added DESeq2 wrapper, and tutorial with colorectal carcinoma data
1.7.3 Added details to the DESeq2 vignette
1.7.3 Some revisions to DESeq2 vignette. Fixed table, added plot
1.7.3 DESeq2 vignette. Remove non-ascii hyphen character.
Merge pull request #253 from joey711/model-wrappers

1.7.3 phyloseq_to_deseq2 function, and new vignette for DESeq2 analysis with Negative Binomial model