Decimal Floating Point types.

[Iain Buclaw]

Speaking on behalf of Dejan, he expressed a wish to have such a 
type in D. (eg: such that assert(3.6 * 10 == 36.0) - which may 
not always be true on all architectures).

As maybe a new backend type is out of the question.  Perhaps we 
should create a new library type for the job - eg: _Decimal32, 
_Decimal64, _Decimal128.

Thoughts?


Regards
Iain.