remove Content-Disposition header from ?raw=1 (fixes #12)

There was a bug in the code that generates the Content-Disposition
header, that prevented ?raw=something from working.
Also, I hate Content-Disposition: attachment anyway (if I want to
save something to a file, that's what "Save As" is for!).
ignore account requests containing "<a href" (fixes #10)

If an account request's comments field contains <a href, it skips all
the code that actually saves the account request, and just displays
the success message. This is a fairly effective antispam measure.