Set removeFromSuperViewOnHide to YES for convenience methods

By setting `removeFromSuperViewOnHide` to `YES` for this convenience method we reduce the chance of memory leaks. People use `[MBProgressHUD showHUDAddedTo:animated:]` together with `hide:` and simply forget to remove the HUD view.

If people want the old behavior, they can simply set `removeFromSuperViewOnHide` to `NO` after calling `[MBProgressHUD showHUDAddedTo:animated:]`.