add save_html and save_json helper functions
add save_html and save_json helper functions

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