add to dub registry

[MartinNowak]

Would be great being able to build this project with dub. http://code.dlang.org/

[p0nce]

So I forked and:

• make it build with latest compilers
• made he pfft.pfft API @nogc nothrow
• added the ability to use through DUB (though only the SSE version will work right now) I should have looked closer since there are branches much more advanced than master in the original repo from @jkrempus This thing is amazing, I get at least 2x faster than FFTReal.

[p0nce]

I should have looked a bit more closely. The branch master is very much behind more recent branches...