Using listview to group referenceview's snaks

The referenceview widget inherits from listview and manages multiple snaklistviews now.
These snakview widgets contain the reference's snaks that feature the same property.

bug: 52391

Change-Id: I4e1a086a0a60da563898e0c0198a0c870aa59853
Merge "Using listview to group referenceview's snaks"