[CM] generators.scm

[Heinrich Taube]

svn has the latest  generators.scm from snd-10 so hopefully the piano  
will work again.

new stuff: new plotter dialogs  Edit Points, Shift Points and Rescale  
Points operate on the current point selection. edit points brings up a  
dialog where you can change the value of any field; shift and rescale  
dialogs operate on the field values displayed on the horizontal or  
vertical dimensions.  the dialogs are minimalist - no buttons, just  
edit the fields and when you press Return in any field the dialog does  
its action.  the rescale points dialog uses cm's rescale function, so  
you can even invert (by making the minimum greater than the maximum).