Fix a couple of bugs found with the static analyzer.

Classes/Managed Objects/TSSTManagedGroup.m

@@ -135,7 +135,9 @@ - (NSURL *)fileURL
 	{
 		fileURL = nil;
 		[[self managedObjectContext] deleteObject: self];
-		[NSApp presentError: urlError];
+		if (urlError) {
+			[NSApp presentError: urlError];
+		}
 	}
 	else if (stale)
 	{

Classes/Managed Objects/TSSTPage.m

@@ -240,7 +240,7 @@ - (NSImage *)pageImage
 - (NSImage *)textPage
 {
 	__block NSData * textData;
-	if(self.index)
+	if(self.index != nil)
 	{
 		[self.group requestDataForPageIndex: [self.index integerValue] completionHandler:^(NSData * _Nullable pageData, NSError * _Nullable error) {
 			textData = pageData;
@@ -302,7 +302,7 @@ - (NSData *)pageData
 {
 	__block NSData * imageData = nil;
 	TSSTManagedGroup * group = self.group;
-	if(self.index)
+	if(self.index != nil)
 	{
 		NSInteger entryIndex = [self.index integerValue];
 		[group requestDataForPageIndex:entryIndex completionHandler:^(NSData * _Nullable pageData, NSError * _Nullable error) {

Classes/Session/TSSTSessionWindowController.m

@@ -1165,6 +1165,9 @@ - (void)changeViewImages
 			titleString = [NSString stringWithFormat:@"%@ — %@", fileName, titleString];
 		}
 	}
+	if (fileName == nil) {
+		fileName = representationURL.lastPathComponent;
+	}
 	if (@available(macOS 11.0, *)) {
 		self.window.title = fileName;
 		self.window.subtitle = [titleString stringByReplacingOccurrencesOfString:[NSString stringWithFormat:@"%@ — ", fileName] withString:@""];

QuickComic/DTPartialArchiveParser.m

@@ -50,7 +50,7 @@ -(void)archiveParser:(XADArchiveParser *)parser foundEntryWithDictionary:(NSDict
 
 	if(!isres)
 	{
-		XADString * name = dict[XADFileNameKey];
+		id<XADString> name = dict[XADFileNameKey];
 		NSString * encodedName = [name stringWithEncodingName:parser.encodingName];
 		// NSLog(@"Encoded Name: %@", encodedName);
 		if([searchString isEqualToString: encodedName])