bin/170206: complex arcsinh, log, etc.

[Stephen Montgomery-Smith]

Yes, everywhere I said "double precision" I meant "doubled precision."

I think the papers by Hull et al were perfectly happy with a ULP of 
around 4.

I have been trying to do a little better, but like you I am noticing 
that log1p isn't that good either.

I have tried some other things.  I am attaching this example which gets 
a ULP a little over 2.  I simulate high precision arithmetic by 
expanding everything out into integers.  I certainly didn't aim for a 
speedy program.