add IsDirectory and support Delete actions

ModpackUpdater/UpdateInstaller.vb

@@ -180,8 +180,14 @@ Public Class UpdateInstaller
                         sRemote.Close()
                         fs.Close()
                     Case UpdateActionType.Delete
-                        If File.Exists(destFilePath) Then
-                            File.Delete(destFilePath)
+                        If action.IsDirectory Then
+                            If Directory.Exists(destFilePath) Then
+                                Directory.Delete(destFilePath, True)
+                            End If
+                        Else
+                            If File.Exists(destFilePath) Then
+                                File.Delete(destFilePath)
+                            End If
                         End If
                     Case UpdateActionType.Copy
                         Dim srcFilePath As String = Path.Combine(localPath, action.SrcPath)