renderer-gst: Use source element for queries.

Fixes querying duration and position.

Fixes DLNA CTT : 7.3.157.8

https://bugzilla.gnome.org/show_bug.cgi?id=721824
all: Update FSF address

Signed-off-by: Jens Georg <mail@jensge.org>

https://bugzilla.gnome.org/show_bug.cgi?id=721575
server: Add LG TV hacks

Signed-off-by: Jens Georg <mail@jensge.org>

https://bugzilla.gnome.org/show_bug.cgi?id=721270
renderer-gst: Don't handle buffering/clock-lost

Signed-off-by: Jens Georg <mail@jensge.org>

https://bugzilla.gnome.org/show_bug.cgi?id=720836
Prepare 0.21.3