* Updates the base API URL to https://api.whitehouse.com/v1
* Removes the need for an API key
* Bumps up R dependency to 2.15. I won't have time to support additional R versions for now
* Adds examples for loading petitions and signatures to the WeThePeopleClient and to the package vignette
* Fixes a bug in the BATCH_SIZES loading. Should return a value instead of a list