[phobos] Proposal of StopWatch module

[SHOO]

(2010/08/20 19:35), SHOO wrote:
> I rewrote:
> http://ideone.com/5IgYU
> How about it?
>
> P.S. I used an immutable struct for the first time...

Oops, I forgot AUTOSTART.
http://ideone.com/GiVmf
AutoStart.yes seems to be slightly redundant.
How about making a special type AutoStart with typedef and a AUTOSTART 
with constant value(enum)?
See also: Line415, Line469, Line474-487