Follow-up to b5a007a683

WIP to G-code export parallelization through pipelining:
GCodeProcessor is called during the G-code export,
the G-code is no more reopened and re-read, but it is pipelined
from the G-code generator.

src/slic3r/GUI/Plater.cpp

@@ -4871,10 +4871,9 @@ void Plater::load_gcode(const wxString& filename)
 
     // process gcode
     GCodeProcessor processor;
-    processor.enable_producers(true);
     try
     {
-        processor.process_file(filename.ToUTF8().data(), false);
+        processor.process_file(filename.ToUTF8().data());
     }
     catch (const std::exception& ex)
     {