Brought up to date.

I have brought dstats up to date such that it is compatible with modern D compilers and passes it's unittests*. I have also added support for dub and will be adding it to code.dlang.org

For now I'm going to maintain my changes as a fork, but it would better if the main repository was up to date, hence this pull request.

If/when this is merged I will redirect the code.dlang.org repository to here instead of my fork.

P.s. If you have the chance to run the unittests (```dub test``` or ```dmd source/dstats/*.d -unittest -main``` in the new layout), could you comment on the printout? I don't know how close those results are supposed to be to the estimates.