Mobile upload of user images are rotated 90° CCW

This seems to be an error with how CarrierWave handles uploads from iPhone and Android devices. Some suggested fixes are [here](https://stackoverflow.com/questions/18519160/exif-image-rotation-issue-using-carrierwave-and-rmagick-to-upload-to-s3/18541893#18541893). The profile images are uploaded sideways, and presumably profile banners would be too.