exact decimal type, was: 12.3*70.95 a little bit weird

I've been traveling and so didn't really enter into this thread except 
to send a note to Stavros.

There is a flag *decfp  in the bigfloat package which changes the 
arithmetic to decimal.
It is used during computation of the (decimal) version of the output.  
It is not sufficient to
merely bind *decfp to T  to make bigfloats run in decimal, but it is 
probably close.

So there is likely to be a way to make all bigfloat arithmetic decimal.  
In fact some early
version of the package was in decimal -- it is just faster to "round to 
nearest even" if
the fraction part of the number is in binary.

I think that the handful of locations where *decfp is checked need to be 
examined, and
also all occurrences of the number 2, where it is explicitly used as a base.

All results must be rounded, and fpround  (which check *decfp) does the 
work.

RJF