0.7.55

## 0.7.55
September 16, 2014

- Image uploading: you can now upload new images in the Optimizely editor and swap
  them in variations
- Added support for changing  UIImageView's `contentMode` property when changing
  images in a variation
- Added callbacks for live variables so that a developer can be notified when live
  variables are updated
- Fixed a bug with MixPanel integration