Log Message:
Import hs-double-conversion-0.2.0.1 as wip/hs-double-conversion.

A library that performs fast, accurate conversion between double
precision floating point and text.

This library is implemented as bindings to the C++ double-conversion
library written by Florian Loitsch at Google:
http://code.google.com/p/double-conversion/

The Text versions of these functions are about 30 times faster than
the default show implementation for the Double type.

The ByteString versions are slower than the Text versions; roughly
half the speed. (This seems to be due to the cost of allocating
ByteString values via malloc.)