Ignore specify pulsestyle_* and *showcancelled directives.
Ignore specify pulsestyle_* and *showcancelled directives.

This patch adds code to silently ignore the specify directives:
  pulsestyle_onevent
  pulsestyle_ondetect
  showcancelled
  noshowcancelled.

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