captcha-handler branch

[Jeremy Whiting]

David, others,

I pushed the first attempty at captcha-handling to the captcha-handler
branch just now.  It depends on Dario's Captcha-authentication branch
of tp-qt so I don't think it's ready for prime time until that gets
merged into tp-qt itself at some point.

It's working here with a proprietary connection manager that
implements captchas just fine.

I do wonder about the ui a bit.  It currently looks a bit weird to me
since the title says stuff like "Enter the text below", maybe I should
make that just a QLabel instead?  I'm also not sure if the key icon on
the left makes sense for captcha or not.

thanks,
Jeremy