Added checkboxes for Twist chain and Rigid chain.

Having a faulty input #5 for Flow, incorrect string instead of the proper true/false variable Rigid,
resulted in the very slow Flow timing!!
Now Flow take less than one second, instead of 3.5 seconds.

After Link1 and Link2 no longer needed for future factories, removed them from the geometry.

Need to do cleanup of removing the factory results, in the event the cancel button is pressed.

Need to do a Twisted link.

- Brian