By removing mutable state in VolumeWiiCrypted, this change makes
partition-related code simpler. It also gets rid of other ugly things,
like ISOProperties's "over 9000" loop that creates a list of
partitions by trying possible combinations, and DiscScrubber's
volume swapping that recreates the entire volume when it needs to
change partition.
Makes the information panel self-contained.
This was done first, as opposed to isolating the GameConfig panel--the
first panel in the group--as this panel had code all over the place in
ISOProperties, so I figured it'd be best to fix this one up first.
