imbo/imbo — pull request #308 by rexxars (2014-11-04 05:07:55+00:00)
Title: Vignette transformation

This PR lands support for the vignette transformation.
See example attached. Documentation should provide necessary information.

![vignette](https://cloud.githubusercontent.com/assets/48200/4895050/819e4bf6-63e0-11e4-8cc9-1dcfd1acafcc.png)