Add fetching of identi.ca and twitter.com statuses

Uses the Twitter v1 API which will stop working soon-ish, but didn't want to get into the mess of having API keys.

Identica support should always work.

    19:28 <@spaceinvader> https://twitter.com/natmorris/status/311180198341144576
    19:28 < transgressionbot> twitter [natmorris] The finest tulip trees! http://t.co/p2d8E1jKEF
    19:28 <@spaceinvader> http://identi.ca/notice/100050160
    19:28 < transgressionbot> identica [rpcutts] @reality have you done much with node?