libvdeplug plugin: vde over serial lines

 This libvdeplug plugin module adds the support of vde over serial lines.
 vdesl supports the rates up to 4Mbps.
 High baud rates may not be supported by the uart hardware or could provide an
 unreliable service due to communication errors. In order to achieve high speeds
 cables should be short and properly shielded against electro-magnetic noise.