Add measurement feature.

README.md

@@ -8,6 +8,7 @@
 * Clock synchronization between sending stack and receiving stack
 * Applications can specify packet-level expiration times
 * Different receive modes for ASAP and time-synchronized operation
+* Passive measurement of propagation delay, bottleneck data rate and packet loss rate
 * Packet-level timing analysis using [X-Lap](http://xlap.larn.systems)
 * [Hardware timestamping support](https://git.nt.uni-saarland.de/LARN/PRRT/wikis/hardware-timestamping)