[gh-388] Add metatag module and UNL mods to support it

sites/all/modules/metatag/LICENSE.txt

sites/all/modules/metatag/arrow-down.png

sites/all/modules/metatag/arrow-right.png

sites/all/modules/metatag/metatag.admin.css

sites/all/modules/metatag/metatag.admin.inc

sites/all/modules/metatag/metatag.admin.js

sites/all/modules/metatag/metatag.api.php

sites/all/modules/metatag/metatag.inc

sites/all/modules/metatag/metatag.info

sites/all/modules/metatag/metatag.install

sites/all/modules/metatag/metatag.metatag.inc

sites/all/modules/metatag/metatag.module

sites/all/modules/metatag/metatag.test

sites/all/modules/metatag/metatag.theme.inc

sites/all/modules/metatag/metatag.vertical-tabs.js

.../modules/metatag/metatag_opengraph/metatag_opengraph.info

...s/metatag/metatag_opengraph/metatag_opengraph.metatag.inc

...odules/metatag/metatag_opengraph/metatag_opengraph.module

sites/all/modules/metatag/metatag_ui/metatag_ui.info

sites/all/modules/metatag/tests/metatag_test.info