Support running ICE lite locally and on a remote

* Parse ice-lite property from remote SessionDescription
* Add option to SettingEngine that allows the local ICEAgent to run
  in lite mode

settingengine.go

@@ -30,6 +30,7 @@ type SettingEngine struct {
 		ICERelayAcceptanceMinWait    *time.Duration
 	}
 	candidates struct {
+		ICELite         bool
 		ICETrickle      bool
 		ICENetworkTypes []NetworkType
 	}
@@ -88,6 +89,11 @@ func (e *SettingEngine) SetEphemeralUDPPortRange(portMin, portMax uint16) error
 	return nil
 }
 
+// SetLite configures whether or not the ice agent should be a lite agent
+func (e *SettingEngine) SetLite(lite bool) {
+	e.candidates.ICELite = lite
+}
+
 // SetTrickle configures whether or not the ice agent should gather candidates
 // via the trickle method or synchronously.
 func (e *SettingEngine) SetTrickle(trickle bool) {