Update release notes, tentatively set a release date for 3.4.

A few whitespace fixes in here too.

RELEASE_NOTES

@@ -1,4 +1,4 @@
-== iperf 3.4 ==
+== iperf 3.4 2018-02-14 ==
 
 * Notable user-visible changes
 
@@ -10,10 +10,11 @@
 
   * A bug in time skew checking under authentication was fixed (#674).
 
-  * IPv6 flow labels now work with multplie parallel streams (#694).
+  * IPv6 flow labels now work correctly with multiple parallel streams
+    (#694).
 
-  * The client no longer closes  its control connection before sending
-    end-of-test  statistics  to  the  server  (#677). This  fixes  a
+  * The client no longer closes its control connection before sending
+    end-of-test statistics to the server (#677). This fixes a
     regression introduced in iperf-3.2.
 
   * Sending output to stdout now makes errors go to stderr, as per
@@ -22,6 +23,12 @@
   * A server side crash in verbose output with a client running
     multiple parallel connections has been fixed (#686).
 
+  * The --cport option can now be specified without the --bind option.
+    Using the --cport option on Linux can eliminate a problem with
+    ephemeral port number allocation that can make multi-stream iperf3
+    tests perform very poorly on LAGG links.  Also, the --cport option
+    now works on SCTP tests (#697).
+
 * Notable developer-visible changes
 
   * iperf3 now builds on (some) macOS systems older than 10.7 (#607).