Added README with source and basic usage

README

+A Two-Way Active Measurement Protocol
+
+Read the RFC: http://tools.ietf.org/html/rfc5357
+
+Heavily based on https://packetblog.wordpress.com/2012/08/24/udp-packet-measurement/
+by Roman Arcea.
+
+
+Installation:
+
+    None, run the files provided.
+
+Requirements:
+
+    python2
+
+Usage instructions:
+
+    On one machine open UDP_client_server.py, change the IP addresses, ports, packet size, etc.
+
+    On the other machine do the same with the UDP_reflector.py
+
+    As default they point to localhost (IPv6), so it is possible to run it on loopback.
+
+    Start UDP_reflector.py first: python UDP_reflector.py
+    Start UDP_client_server.py: python UDP_client_server.py
+
+    Stop with CTRL+C
+
+    A .csv file will be generated containing statistics.