Improve the texcache hash (sse only) and sse texcache color conv

This texture hash doesn't seem much slower (@solarmystic, would appreciate confirmation on older hardware), and seems stronger.  Unfortunately, it makes it different from the generic / Android implementation, but that would be much slower if I changed it too.

I'm thinking of doing a NEON library/detection thing sometime soon, but expecting it to be annoying...

Also wrote the color swapping in SSE, it's faster for sure (43%?), which does seem to help FF2 for me.

This may possibly help #2673, but I don't know specifically if it does.  It definitely helps Tales of Phantasia X.  So far I have not noticed any glitches.

-[Unknown]