Relax the requirement on list of port declarations for implicit ports.
Relax the requirement on list of port declarations for implicit ports.

Previously list of port declarations were considered a complete
definition of the port. This caused problems for some, so this patch
allows implicitly defined ports (no wire/reg/etc.) to have net
declarations in the body.

CastMi/iverilog,CastMi/iverilog,themperek/iverilog,CastMi/iverilog,themperek/iverilog,themperek/iverilog