Handle multiplatform gems in pessimize-gem-version
Handle multiplatform gems in pessimize-gem-version

* Lazily, by just finding the version that says "ruby"

* Matching each platform and version to the correct bundler name for
  the platform is left as an exercise to the reader. Sure ruby matches
  mri and java matches jruby, but does x86-linux match mingw or
  x64_mingw or neither, etc

dbrady/bin,dbrady/bin,dbrady/bin,dbrady/bin,dbrady/bin