[Playlist Storage] Add another compatibility hook

Add a compatibility getter/setter for URL, which was renamed to url, due
to Core Storage having a requirement of all attributes starting with a
lower case letter.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Playlist/PlaylistController.m

@@ -1348,7 +1348,7 @@ static inline void dispatch_sync_reentrant(dispatch_queue_t queue, dispatch_bloc
 
 	NSWorkspace *ws = [NSWorkspace sharedWorkspace];
 
-	NSURL *url = [[self selectedObjects][0] URL];
+	NSURL *url = [[self selectedObjects][0] url];
 	if([url isFileURL]) [ws selectFile:[url path] inFileViewerRootedAtPath:[url path]];
 }
 

Playlist/PlaylistEntry.h

@@ -64,6 +64,7 @@
 @property(nonatomic) NSData *_Nullable albumArtInternal;
 
 @property(nonatomic) BOOL Unsigned;
+@property(nonatomic) NSURL *URL;
 
 - (void)setMetadata:(NSDictionary *_Nonnull)metadata;
 

Playlist/PlaylistEntry.m

@@ -471,6 +471,16 @@ NSURL *_Nullable urlForPath(NSString *_Nullable path) {
 	self.unSigned = Unsigned;
 }
 
+// More of the same
+@dynamic URL;
+- (NSURL *)URL {
+	return self.url;
+}
+
+- (void)setURL:(NSURL *)URL {
+	self.url = URL;
+}
+
 - (void)setMetadata:(NSDictionary *)metadata {
 	if(metadata == nil) {
 		self.error = YES;