remove support for python 2.6 since scikit-bio doesn't work with 2.6
remove support for python 2.6 since scikit-bio doesn't work with 2.6

napsternxg/pyLDAvis,tdhopper/pyLDAvis,codingafuture/pyLDAvis,kcompher/pyLDAvis,bmabey/pyLDAvis,bmabey/pyLDAvis,tdhopper/pyLDAvis,tdhopper/pyLDAvis,bloody76/pyLDAvis,napsternxg/pyLDAvis,bloody76/pyLDAvis,kcompher/pyLDAvis,codingafuture/pyLDAvis,log0ymxm/pyLDAvis,codingafuture/pyLDAvis,log0ymxm/pyLDAvis,bmabey/pyLDAvis,kcompher/pyLDAvis,log0ymxm/pyLDAvis,napsternxg/pyLDAvis,bloody76/pyLDAvis