Add #273 to History
Update Manifest
Prevent useless relinking when packaging

Previously rake would relink everything in the package directory even
when no file had changed.  This occurred because rake was told the
package directory was a file so it would attempt to recreate it by
linking all the files.

Now Rake knows the package directory is a directory and will not attempt
to recreated it unless the package file list changes.

Fixes #276