Fixed a bug that restoring files doesn't work due to missing parent directory

The root cause was path.Dir can't handle Windows paths that use \ as the
separator.

src/duplicacy_backupmanager.go

@@ -899,7 +899,8 @@ func (manager *BackupManager) Restore(top string, revision int, inPlace bool, qu
 				continue
 			}
 		} else {
-			err = os.MkdirAll(path.Dir(fullPath), 0744)
+			parent, _ := SplitDir(fullPath)
+			err = os.MkdirAll(parent, 0744)
 			if err != nil {
 				LOG_ERROR("DOWNLOAD_MKDIR", "Failed to create directory: %v", err)
 			}

src/duplicacy_utils_others.go

@@ -88,3 +88,7 @@ func (entry *Entry) SetAttributesToFile(fullPath string) {
 func joinPath(components ...string) string {
 	return path.Join(components...)
 }
+
+func SplitDir(fullPath string) (dir string, file string) {
+	return path.Split(fullPath)
+}

src/duplicacy_utils_windows.go

@@ -126,3 +126,8 @@ func joinPath(components ...string) string {
 	}
 	return combinedPath
 }
+
+func SplitDir(fullPath string) (dir string, file string) {
+	i := strings.LastIndex(fullPath, "\\")
+	return fullPath[:i+1], fullPath[i+1:]
+}