[phobos] std.path proof of concept

[Walter Bright]

Steve Schveighoffer wrote:
> I would make a suggestion that the Windows version allows forward slash for a dir separator as input.  "C:/foo/bar.txt" and "C:\\foo/bar.txt" are both valid paths on Windows.
>
>   

True, but you have to be careful using / on Windows, because I regularly 
run into situations where it does not work. std.path should be able to 
correctly read and parse input that uses /, but its output should always 
favor \