lilypond-book: fix quoted html options

[John Williams]

This patch makes lilypond-book properly handle quoted html attributes.

I thought it was surprising and undocumented that
  <lilypond option="quoted option">
is not parsed correctly, so this fixes that.

Currently, it gives you an option called 'option' with the value '"quoted'
and a second option called 'option"' with no value.

~ John Williams

htmlquote.patch
Description: Text document