Support requests >= 1.0.

This is a annoying, but anyone who pip installs requests (currently at 1.1.0) to satisfy your requests >= 0.14 dependency is in for a world of pain.  Might as well just force people to use the new version.

This very issue is discussed by @dcramer here: http://justcramer.com/2013/01/29/dependency-graphs-and-package-versioning/