Split up the forward DCT routine into three stages

Divide it into sample conversion, DCT and quantization in order to
easily provide alternative implementations of each stage.


git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@13 632fc199-4ca6-4c93-a231-07263d6284db
2 files changed