To forward a remote usb device over usbip the following steps is required: 1. Execute "usbip bind" on remote end. 2. Execute "usbip attach" on local end. These steps must be perfomed in above order and after usb device is plugged in. If the usb device is unplugged on the remote end the steps above needs to be performed again to establish the connection. This patch set implements a feature to persistently forward devices on a given bus. When using flag "-p|--persistent" on remot end, the USB device becomes exported when plugged in. When using flag "-p|--persistent" on local end, the USB device becomes imported when available on remote end. Thus it is only required to run the usbip command once on each end, in any order, to persistently forward usb devices on a given bus. This is sent in three separate patches: tools/usbip: add usb event monitor into libusbip tools/usbip: export USB devices on a given bus persistently tools/usbip: import USB devices on a given bus persistently
