This change allows developers to build and install the latest versions of Grilo and Grilo-plugins when building Totem from source. This can be useful for Totem developers (to test against latest changes in Grilo), and for Grilo plugin developers (to test their plugins inside Totem).
It adds an optional dependency on grilo-plugins. Totem already uses some of the plugins from this package but didn't express a dependency before.
Depends on: grilo-plugins!69 (merged)