TPAC: Improve copy display in record summary

TPAC: Improve copy display in record summary

In the copy counts, offer a link to display the copies at parent
libraries that have available copies. For example, if you are browsing
at BR1 and there are no available copies, but you see that SYS1 has
available copies, clicking "(Show)" beside the SYS1 available copy count
will change the search scope to SYS1 and display the copies for BR1 and
BR2.

Also, avoid displaying the copy table header if there are no physical
copies to display (for example, if there are located URIs that make the
copy show up in search results).

Signed-off-by: Dan Scott <dan@coffeecode.net>