Provide a more thorough description of the trade-offs between the various DCT/IDCT algorithms, based on new resarch


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1287 632fc199-4ca6-4c93-a231-07263d6284db
Port the more accurate (and slightly faster) floating point IDCT implementation from jpeg-8a and later.  New research revealed that the SSE/SSE2 floating point IDCT implementation was actually more accurate than the jpeg-6b implementation, not less, which is why its mathematical results have always differed from those of the jpeg-6b implementation.  This patch brings the accuracy of the C code in line with that of the SSE/SSE2 code.


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1288 632fc199-4ca6-4c93-a231-07263d6284db
Document the fact that the fast integer FDCT is not fully accelerated for quality levels above 97 + additional wordsmithing


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1290 632fc199-4ca6-4c93-a231-07263d6284db
Use 2-space indentation for the enums, to be consistent with the structs


git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1292 632fc199-4ca6-4c93-a231-07263d6284db