Support a new secret user default JalkutRespectFolderExpansionOnNextUnread, and revise the "next unread" strategy so that whether the search for a next unread wraps around to the top or not is parameterized.

Shared/Timeline/ArticleArray.swift

@@ -20,18 +20,21 @@ extension Array where Element == Article {
 		return self[row]
 	}
 
-	func rowOfNextUnreadArticle(_ selectedRow: Int) -> Int? {
+	func orderedRowIndexes(fromIndex startIndex: Int, wrappingToTop wrapping: Bool) -> [Int] {
+		if startIndex >= self.count {
+			// Wrap around to the top if specified
+			return wrapping ? Array<Int>(0..<self.count) : []
+		} else {
+			// Start at the selection and wrap around to the beginning
+			return Array<Int>(startIndex..<self.count) + (wrapping ? Array<Int>(0..<startIndex) : [])
+		}
+	}
+	func rowOfNextUnreadArticle(_ selectedRow: Int, wrappingToTop wrapping: Bool) -> Int? {
 		if isEmpty {
 			return nil
 		}
 
-		var rowIndex = selectedRow
-		while(true) {
-
-			rowIndex = rowIndex + 1
-			if rowIndex >= count {
-				break
-			}
+		for rowIndex in orderedRowIndexes(fromIndex: selectedRow + 1, wrappingToTop: wrapping) {
 			let article = articleAtRow(rowIndex)!
 			if !article.status.read {
 				return rowIndex