It is important that the user be able to place a top-level doc-files directory
in the source tree, for putting the copyright.html, logos and other files that
are not specific to any one package. Javadoc does not currently copy this
directory to the destination, but should.
One developer has asked for a generalization of this feature, where
a doc-files directory can be placed in *any* source subdirectory
below the root in the package path and javadoc will copy it.
For example, com.mycompany.mypackage could have a doc-files
directory at com/doc-files, even though com is not technically
a package (because it contains no source files).
Note: Files in doc-files are not processed, and so the copyright page will
not have the navigation bars at the top and bottom.