Updated imports to include gWidgets - imported entire package, rather
than specifying individual functions.
Updated gelScan, now includes a minimal scrolling interface for viewing
bins as 'gels'. Uses local variables defined within the environment of
scanGel(), which may be the best way to deal with updating the view
range? Not sure about this yet.
Updated help files to reflect previous 2 commits ed74a99 and 6fc69cf