Add example.

README.rst

@@ -6,6 +6,27 @@
 
 nfstream is a flexible and lightweight network data analysis library.
 
+**nfstream main features**
+
+* **Performance:** nfstream was designed to be fast, CPU savvy and small memory fingerprint.
+* **Layer-7 visibility:** (250+ applications including Tor, Messenger, WhatsApp, etc.).
+* **Flexibility:** Missing metric? You can add a metric in 2 lines of code using nfstream User Defined Metrics.
+
+**examples of use**
+
+Dealing with a big pcap file and just want to see flow informations stored in as a csv file or
+pandas Dataframe? nfstream make this path easier in few lines:
+
+.. image:: docs/source/streamer_example.png
+  :scale: 80%
+  :align: center
+
+
+.. code-block:: json
+
+    {"ip_src": "192.168.43.18", "src_port": 52066, "ip_dst": "66.220.156.68", "dst_port": 443, "ip_protocol": 6, "src_to_dst_pkts": 9, "dst_to_src_pkts": 10, "src_to_dst_bytes": 1345, "dst_to_src_bytes": 4400, "application_name": "TLS.Facebook", "start_time": 1472393122365, "end_time": 1472393123665, "export_reason": 2}
+
+
 Getting Started
 ===============