grilo: Add and use new strv_has_prefix() helper
grilo: Remove duplicate metadata keys

Use the same keys for search and browse.
grilo: Make default items 256 pixels in height
grilo: Use content-loading icon for thumbnailing icon
grilo: use a 16x16 icon for the thumbnailing icon

As that's the "native" size of the icon, and it prevents fuzziness.
grilo: Handle series episodes better

Use show name, season and episode numbers when available.
grilo: Add "delete-button-sensitive" prop to selection toolbar
grilo: Add Delete support
grilo: Get out of selection mode when playing starts
libgd: Update to get the small subtitle support in view