Log Message:
Updated py-html2text to 2016.9.19.

2016.9.19
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* Default image alt text option created and set to a default of empty string \ 
"" to maintain backward compatibility
* Fix #136: --default-image-alt now takes a string as argument
* Fix #113: Stop changing quiet levels on \/script tags.
* Merge #126: Fix deprecation warning on py3 due to html.escape
* Fix #145: Running test suite on Travis CI for Python 2.6.