Fix for i18n, details page, "Categories" heading
i18n for queued images which have yet to have a title entered

This is only seen from the My Uploads page.
i18n for "Read about licensing" label on License page

The key was present in the language files, but the value wasn't being used anywhere.
i18n for add category page title and search box placeholder text
Merge pull request #87 from montehurd/missingI18N

Fixes for various missing i18n