#1 Incorporate Rio tools

[Mike Larsen]

Add functionality such that a playlist can be built to
a certain size (in my case <= 64M), the selected mp3
files copied to a staging area, and then loaded into a
Rio (I have a 600, use rioutil to fill it).
Incorporate the functionality into command line (with
switches) and GTK (with "Stage" and "Rioload" buttons)
interfaces.