Implementing Half Floats in D

[Walter Bright]

On 1/29/2013 4:31 AM, Don wrote:
> Since it got lost in the old thread on this topic, I'll repost my versions of
> floatToshort and shortToFloat, which are extremely fast (no unpredictable
> branches, no lookup tables) and respect the current rounding mode:

I was waiting on incorporating your improvements until after std.halffloat was 
merged into Phobos. This is because the old ones were easier to understand, and 
I wanted them in the repository history.