SDWebImageDownloaderOperation: pass orientation to initWithCGImage during progressive rendering

Hi! I'm a developer from Fog Creek Software in NYC. I work on the Trello iOS app; for 2.5 we started using SDWebImage's progressive rendering option. We love it! Here's a bugfix for a small bug we noticed when we were progressively rendering JPEGs with orientation.

Here's an image we used for testing. It has EXIF orientation of 6 (UIImageOrientationRight).
https://f.cloud.github.com/assets/63533/2151861/d08238f8-9411-11e3-886a-04ab0d72832a.jpg