The groundwork has now been laid for per sheet instance data. Initially
this only supports sheet page numbers but could be expanded to include
other per sheet instance information.
ADDED: Support for user defined schematic page numbers.
When creating an unique filename to plot a subsheet, the subdirectory name is
used to create the unique filename, but should not be used as a directory,
otherwise the plot file is not created at the right place (and sometimes
cannot be created)
Marek Roszko
Wayne Stambaugh
jean-pierre charras
Jeff Young