main: Don't add the playlist to the sidebar
main: Remove "Save playlist" from playlist widget

It's completely unused now.
main: Remove up/down buttons in playlist widget
main: Remove save property from playlist

Left-over bits from ec64084c71290557819ee007b969f080747e36e5
main: Make debug playlist widget bigger
grilo: Fix griloresources.h/.c generation

By adding them to BUILT_SOURCES.

https://bugzilla.gnome.org/show_bug.cgi?id=722719