(They'll just point to temp files anyway.)
Also moves schematic netlist fetching to
MAIL_SCH_GET_NETLIST.
Eeschema's generateSchematicNetlist() hasn't
worked in some time.
Also suppresses parity error counts when parity
not run due to failure to find or load schematic.
Also writes out ERC/DRC reports even when they're
set to fail the job.
Also improves adding/removing netlist exporters to
select an appropriate tab in the dialog (either
the newly-created one or the one preceeding the
deleted one).
