Changed mime type for MNG from image/png to image/x-mng and JNG to image/x-jng
Changed mime type for MNG from image/png to image/x-mng and JNG to image/x-jng


git-svn-id: 7f11a4e55de7d4642c7675696f15857479c93c9d@12958 aa41f4f7-0bf4-0310-aa73-e5a19afd5a74

svn2github/ImageMagick,svn2github/ImageMagick,svn2github/ImageMagick,svn2github/ImageMagick