Comment 40 for bug 1712854

I've updated the branch with three commits:

1) Fix a thinko in grid action handler names for cancel/uncancel
2) Provide a "only last hold for copy" option for the wide hold api to address the "duplicate copy" issue
3) Make use of the in-browser cache of holds when switching between All and Clearable lists, as the act of clearing holds can take care of updating the in-browser data.