If cells are instanced before being defined, causing the GDS parser
to rewind the cell from the top, then the "already defined" error
messages will be suppressed, since it is to be expected that cells
will be seen twice (and ignored the 2nd time). When rewinding, an
output message is issued so that it is clear that the file contains
instances that are used before they are defined, and recommends the
"gds ordering on" setting. Also: Fixed the "gds ordering" command
code so that the command with no third argument returns the state
of the "gds ordering" setting instead of generating a parser error.
453d276f20