Can input xy pairs into SigBufferXY, it doesn't interpolate between pairs, also is drawing upside down (need to subtract y from preview height).
More protection around browsing dir, will add ability to browse non directories next.  Maybe want to be able to browse but then hit another key to confirm selection, so the act of browsing doesn't effect downstream nodes.
Renamed image_names to more accurate and general file_names.
Can browse to files now, though the system is a little odd and the code a little clunky.  Really want to be able to browse and perhaps even see previews of images or dirs (thumbnail the first image in the directory) or videos or graph files.
Want to be able to browse but have another key to commit current selection to
an output 'selected_path' or similar.