Support full bitcoin integration in Gittip

[reedlaw]

I've opened an issue proposing how bitcoin could be fully integrated into Gittip.com. If you know what Gittip is and support this, or have any suggestions on how to implement recurring payments with bitcoin, please feel free to add to the conversation on the github issue. Comments count as +1 in support of the issue. But of course, only post if you really want to see this happen. I've already issued a pull request for adding a bitcoin address field to the user profile.