morebits: use innerHTML for printUserText message header, not textContent; use in ARV

[Amorymeltzer]

Swaps textContent out for innerHTML in the p element (the header). Doing so allows the use of html (go figure), which menas we can link to AIV and UAA to close #590. Shouldn't have any noticeable effects otherwise?

Alternatively, we could add some selector to either/both printUserText elements then work on that directly.

[siddharthvp]

Alternatively we could allow wikilink syntax in the message and setup printUserText to render the wikilinks. This would be nice to have in the Morebits.status constructor as well.

[Amorymeltzer]

That's an interesting idea for Morebits.status, what'd you have in mind? I'd imagine that'd look something like having a linkifier function that pulls out (unbinder?) anything that looks like a wikilink and passes the rest as text?