Indicate type of object in collection.
Add visitor to select siblings.
Select the siblings when an image of a MIF is selected.
Use Set instead of List.
Fix multi-selection and highlight of MIF.
Highlight node when multi-selection happens in tree.
Remove duplicated code to change color of the nodes.
Fix multi-selection issue in data manager tree (see #10855)
Add node-walking method to ImageTable.

This commit cleans imports and commented out code and adds a method
for highlighting TreeTable nodes that are part of a MIF.
Add missing comments.
Add method for changing colour in ImageTableNode.
Enable TreeTable node highlighting.
Implement rudimentary node highlighting
Remove unused method.
Fix MIF highlight in table view.
Add colour preset for MIF highlighting.
Use colour preset when highlighting MIFs.
Merge pull request #1169 from bpindelski/mif-highlight

Add MIF highlighting in Insight (see #10778)