Add an option to strip text inside html tags

[Tratoschek]

It would be nice, if you could add an option to strip text inside html tags. Sometimes poorly formatted webpages provide such text.

• Version by pyhtml2text --version: pyhtml2text 2016.5.29
• Test script

>>> import html2text
>>> html2text.html2text('<b>text </b>')
'**text **\n\n'

Much better would be '**text**\n\n'

• Python version python --version: Python 3.4.3

[theSage21]

This seems reasonable. I'll get to it in a while if that's ok. In case you want to you could submit a PR for this.

[jonathan-s]

Fixed by #177