Add feature #627 and fix bug #628

- Feature: Option to overwrite existing audio files when moving to Books
- Bugfix: Do not set liberated status if moving files fails.

Source/FileLiberator/ConvertToMp3.cs

@@ -73,8 +73,23 @@ namespace FileLiberator
 						}
 						else
 						{
-							var realMp3Path = FileUtility.SaferMoveToValidPath(mp3File.Name, proposedMp3Path, Configuration.Instance.ReplacementCharacters, "mp3");
-							OnFileCreated(libraryBook, realMp3Path);
+							try
+							{
+								var realMp3Path
+									= FileUtility.SaferMoveToValidPath(
+										mp3File.Name,
+										proposedMp3Path,
+										Configuration.Instance.ReplacementCharacters,
+										extension: "mp3",
+										Configuration.Instance.OverwriteExisting);
+
+								OnFileCreated(libraryBook, realMp3Path);
+							}
+							catch
+							{
+								return new StatusHandler { "Failed to move decrypted files to Books directory" };
+								throw;
+							}
 						}
 					}
 					catch (Exception ex)