[phobos] Starting work on std.time

[Yao G.]

This has been a busy week, so I didn't have much time to work on the date  
time modules I'm porting. But I started the work on one of the Time  
components: TimeDuration. Here's the code:

http://ideone.com/3yNG6

It still needs more polish, better docs and more comprehensive unit test.  
But it works. The main issue it could have is that it needs another  
internal module to work, because the TimeDuration struct supports special  
values (+infinite, -infinite, NAN, etc.), and to add support for those,  
some helper structs had to be ported. Here's the internal, impl module in  
question:

http://ideone.com/g9IWA

On the other hand, I did a quick dive on Johnathan code, and I think it's  
superb. I think it deserves a review, because it could be a better  
candidate to inclusion that mine. I'll continue porting the Boost date  
time library, because as I'm using it on my own code, but obviously the  
better one should be picked.


--
Yao G.