`islicer` keeps a reference of the data

[paskino]

islicer keeps a reference of the data to plot. Even deleting the islicer object or the cell it is in doesn't allow to free the memory. Line 273 in the code block below is the reference to the data.

CIL/Wrappers/Python/cil/utilities/jupyter/__init__.py

Lines 271 to 292 in 8389430

	out = interactive_output(
	display_slice(
	container,
	minmax,
	direction,
	title=title,
	cmap=cmap,
	size=size,
	axis_labels=axis_labels,
	origin=origin),
	{'x': slice_slider,
	'minmax': min_max,
	'roi_hdir': roi_select_hdir,
	'roi_vdir': roi_select_vdir,
	'equal_aspect': equal_aspect})
	box = widgets.HBox(children=[out, selectors],
	layout=widgets.Layout(
	display='flex',
	justify_content='center'))
	return box