Fix viewport on Inform7 Standard template.

[pteromys]

In Inform7-6M62, the Standard template is incompatible with two of the styles introduced in 71fc32c4bc0bd8d264c57c9196f611b9221d3756:

• "width: 100%" because the interpreter runs in div#gameport, whose width is the window width minus 15.4em;
• "overflow: hidden" because, at least the way ifvms.js does it now, nothing inside div#gameport has overflow: scroll or auto so this would break scrolling, which I think is the symptom seen in #37.

So override those styles in an embedded stylesheet in the HTML head material provided to Inform 7.

Longer-term, if Inform 7 wants to use quixe through parchment rather than as a separate template, it'll need to rename #gameport because the id collides with an internal div used by quixe. (That or parchment can rename gameport in quixe-runner.js, in (a) the HTML fragment and (b) adding gameport: "whatever_the_new_name_is" to the set_page_title line; but making that change would surprise anyone who has customized a template with styles on #gameport.)

[pteromys]

I believe this fixes #37 but since I'm not certain I've interpreted it correctly, we might want to see if either of @nickbe or @andrewschultz can be reached to verify.

[curiousdannii]

This looks good, but can you change it to not update the dates for the files which weren't modified? (Yes this is nonideal, and in the future I'll move away from having dates in the headers.)

[curiousdannii]

Actually it doesn't really matter, I'm planning to overhaul this all soon anyway.