use straight patch cords for Vanilla GUI preset

This implements straight patch cords for any GUI preset that has the substring "vanilla"

Issues:

• it doesn't immediately redraw all the open patches to adjust the lines. So if the user changes the preset in a running instance they could get a mix of curved and straight lines.

Is there a convenience function in the GUI to walk all open patch windows so we can send an unmap/map message to redraw them?