[CM] Doubling selection size in SND scm

[John Mullins]

Hey,
    Thanks for the help with the mp3's, found the function in
misc.scm.  I'm trying to mimic sound forges acid looping "tools".  I'm
trying to make it so you can double the selection size, or halve it.

I know selection-frames returns how many frames are selected, but I
can't seem to set selection-frames to anything different.

Any help is very appreciated.

Thanks, John.