Use dub to create source lib and executables

[Richard (Rikki) Andrew Cattermole]

Yes dub was setup to cover the most common cases, but ignores when you 
have multiple outputs. Not ideal.

There is a PR to add build steps currently, which will help improve 
things, so there is work to make dub better at these less common use cases.

The simplest solution is to do one package per binary, then use a shell 
script to trigger them in succession, not great but a workable solution.