Bug 19490: Add a 'Holds' column to the items batchmodification tool

Bug 19490: Add a 'Holds' column to the items batchmodification tool

To test:
1 - Add some items to bathc modification
2 - Note there is no indication fo holds
3 - Apply patch
4 - Reload and note you can see how many holds (or none)
5 - Note you can hide this column with css:
    #batchMod-edit .holds_count { display: none; }
6 - Note the column has a tooltip to indicate item vs. record holds

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>