Merging the pslib "additional" functions from the modules into psLib proper.
Added jpeg directory for psImageJpeg.
Changes to build system (configure.ac, and various Makefile.am)
psVectorSmooth: changed API to allow optional output vector
psSparse: changed sizes to type "long"; added "const"
psRegionIsBad: Renamed psRegionIsNaN
psImageBicubeFit: changed sizes to "long"; added a "const"
psLine: changed sizes to "long"
psImageUnbin: description required in SDRS
psImageClippedStats: renaming to psImageBackground; removing static structures; API changed!
psImageFlipX, psImageFlipY merged to psImageFlip
psStringSubstitute: added "const"
