htmlext: --version: add license type, copyright info and link to online documentation
htmlext: --version: add license type, copyright info and link to online documentation

thomastrapp/hext,thomastrapp/hext,thomastrapp/hext,thomastrapp/hext,thomastrapp/hext,thomastrapp/hext,thomastrapp/hext,thomastrapp/hext