Updated Twitter plugin to be compatable with v1.1 API. 

NOTE: API libraries currently require the use of OAuth Token and OAuth Token Secrets, so it is highly advised to remove all WRITE operations from the plugin. I did not do so because I'm unsure of who's using the Twitter plugin.

@elazar: I created a Twitter account for the express purpose of creating an application to obtain consumer/oauth tokens and secrets, get ahold of me via email tomorrow and I'll get you the account credentials (and swap the email registered with the account over) for deployment to the main Phergie instance.