Made to work with Unity's 2D Toolkit. Converts @4x images to @2x and normal images. Also converts -ipadhd and -hd suffixes to @4x and @2x conventions.
Changed it so it converts normal images to @1x
Changed the downscaling to use CGImageRef instead of UIImage. Slightly higher quality scaling. Code is a bit more messy.
Update README.md
Merge branch 'Unity-based'
Merged in updates and bug fixes from Unity branch. And did a little refactoring.