Clarify how to do a 64-bit build using the Visual Studio IDE


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1247 632fc199-4ca6-4c93-a231-07263d6284db
Minor comment correction (we support the full range of IDCT scaling factors now.)


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1249 632fc199-4ca6-4c93-a231-07263d6284db