Description: Adding a utility class that can detect subsampling, compression quality and huffman optimization properties for jpeg images. This can aid in doing more intelligent optimizations for jpegs in image compression rewriters such as BasicImageRewriter. For e.g. an image with low compression quality (e.g. 50) need not be compressed with quality 90 since this will only result in increasing the image size. (Jpeg Reference: http://www.bsdg.org/swag/GRAPHICS/0143.PAS.html)
Please review this at http://codereview.appspot.com/3165041/ Affected files: java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/image/JpegImageUtils.java java/gadgets/src/test/java/org/apache/shindig/gadgets/rewrite/image/JpegImageUtilsTest.java java/gadgets/src/test/resources/org/apache/shindig/gadgets/rewrite/image/testImage420.jpg java/gadgets/src/test/resources/org/apache/shindig/gadgets/rewrite/image/testImage444.jpg java/gadgets/src/test/resources/org/apache/shindig/gadgets/rewrite/image/testImageNotHuffmanOptimized.jpg
