The new build script written in D

[kntroh]

I thought, ruby is should be no need to building of DWT2.
So I ported DWT2 rakefile and some of functions of the rake to D script.
I have tested this script at Windows 7 and Ubuntu, it seems to be working well.
https://github.com/kntroh/dwt/tree/newBuildScript

But, this script doesn't work on D1 with Tango.

If there is no problem, I will send a pull request.