Add additional logic for included files in package

[yeazelm]

Homebrew can't reuse a Keg exported from this tool because of the way
the rsync copies the files and dereferences the symlinks. This still
produces a working package, but Homebrew complains about it. This commit
adds in the additional logic needed to produce a tree in the package
that let's Homebrew reference and use the Keg as if Homebrew had
installed the Keg rather than via a pkg. The key value to this change is that the resulting
package can be used to "bootstrap" the package via a package and then let Homebrew
maintain it after the fact.