Update envoy!

Updated a whole lotta things.

Let me know if you'd anything in a separate pull request

 - Updated license file
 - pep8 style fixes
 - ConnectedCommand std_out and std_err now mostly work
 - Tests all pass on py 2.6 & 2.7 & 3.2 & 3.3 (on my machine)

Might want to consider dropping saying you support 3.1 in the classifiers?