Idea: Support for a single 'fat' binary supporting multiple buildpacks

[spew]

A common problem across buildpacks is that when combining related buildpacks into a docker image, many small binaries are created, each with almost the same content. The request is for a mechanism to be created for collapsing multiple buildpacks down into a single binary and then have the individual buildpacks link to this binary and be invoked through some heuristic (perhaps detecting based on filename).