Add recipe for imageio

Imageio just went 1.0. Main website: imageio.github.io

Question: I build this package and uploaded to binstar (pyzo channel). The convert command is awesome, but the build is still bound to a certain Python version (and even to a certain numpy version if you make that a run dependency). I know that the same code runs from 2.6-3.4. Is there a way to convert it for other versions, or to build it in a way that it is python version agnostic?