Bug 8995: (follow-up) Add tests, move open_url/coins routines to Koha namespace

Bug 8995: (follow-up) Add tests, move open_url/coins routines to Koha namespace

Test plan:
1) Ensure the COinS span tag is still included on this pages. You need
to look into html source and search for span tag with class 'Z3988',
   which has COinS string in title.
   Staff client:
       catalogue -> ISBDdetail
       catalogue -> MARCdetail
       catalogue -> detail
       virtualshelves -> shelves
    OPAC (you should have COinSinOPACResults system preference enabled):
        opac detail
        opac search
        opac shelves
2) Run tests:
prove t/Biblio.t t/db_dependent/Biblio.t t/db_dependent/Koha/Biblio.t

Signed-off-by: Magnus Enger <magnus@libriotech.no>
Tested with all 9 current patches. Works as advertised, including
OPACURLOpenInNewWindow. If a record has no items, no OpenURL link
is displayed. All the suggested tests pass. I did not test with
XSLT turned off.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>