Re: Statistics Import and Export

if you want everything --include=schema,data,statistics (presumably
redundant with the default behavior)
if you want schema only --include=schema
if you want "everything except schema" --include=data,statistics

Until we add a fourth option, and then it becomes completely ambiguous as to whether you wanted data+statstics, or you not-wanted schema.

And if someday, for example, there is ever agreement on including role
information with normal pg_dump, you add "roles" as an option to be
parsed via --include without having to create any new flags.

This is pushing a burden onto our customers for a parsing convenience.