merged: add escape_tags option to enable/disable escaping tag names and attribut...

[scythargon]

...es from @trbs

[mankyd]

I am reviewing this (sorry for the super unreasonable delay). My hesitation in merging is that this produces invalid HTML.

I am thinking the minifier should do it the hard way and deal specifically with "ambiguouos ampersands":

https://www.w3.org/TR/html5/single-page.html#syntax-ambiguous-ampersand