Bug 2044: allowing multiuple icon sets

Bug 2044: allowing multiuple icon sets

I've rearranged the two directories where media type icons live.
I've also added two more collections of icons, one from
http://apps.carleton.edu/campus/library/bridge_icons/
and one from liblime (Tina). The first has a license restriction that I added
to the "Licenses" tab on the "About" page.

Then, I've adjusted the Item Types Administration page so that it can deal
with multiple collections of icons.

I also added a test script to verify that the two identical icon directories
are actually identical.

DOCUMENTATION CHANGE: It's possible that we need to add something to the administration
documentation to indicate how you can add more sets of icons if you want. You simply add
directory to koha-tmpl/intranet-tmpl/prog/img/itemtypeimg/ and to
koha-tmpl/opac-tmpl/prog/itemtypeimg. The icons should start showing up.

Signed-off-by: Joshua Ferraro <jmf@liblime.com>