d.godbolt.org now supports DMD

[Seb]

Thanks to the work of Rabs Rincon [1] DMD is now supported on 
https://d.godbolt.org

A simple example of comparing DMD's object code with LDC's + 
GDC's output:

https://godbolt.org/g/EQCTNy

[1] https://github.com/mattgodbolt/compiler-explorer/issues/306