sgi -- bug fix for the case of 16 bpp RLE encoding, was double-swapping bytes
Update testsuite reference output after recent sgi reader fix
Add 'safe' inversesqrt, log, log2, log10, logb.
Add appropriate 'using' statements so certain functions are available on
platforms that don't have them in their standard libary.
oiiotool - fix minor bug where tiled files were output inappropriately.