More wording tweaks in doc files.

README.md

@@ -21,7 +21,7 @@ Note that iperf3 is *not* backwards compatible with the original iperf.
 Primary development for iperf3 takes place on CentOS Linux, FreeBSD,
 and MacOS X.  At this time, these are the only officially supported
 platforms, however there have been some reports of success with
-OpenBSD, Android, and other Linux distributions.
+OpenBSD, NetBSD, Android, Solaris, and other Linux distributions.
 
 iperf3 is principally developed by ESnet / Lawrence Berkeley National
 Laboratory.  It is released under a three-clause BSD license.
@@ -37,9 +37,9 @@ Downloads of iperf3 are available at:
 
     http://downloads.es.net/pub/iperf/
 
-To check out the most recent code, do:
+To check out the most recent code, clone the git repository at:
 
-    git clone https://github.com/esnet/iperf.git
+    https://github.com/esnet/iperf.git
 
 Building iperf3
 ---------------

RELEASE_NOTES

@@ -15,8 +15,8 @@ functionality in iperf 3.1.0, but not present in 3.0.11 or any earlier
     called --congestion (the old --linux-congestion option works
     but is now deprecated).
 
-  * Added -I flag for the server to write a PID file, mostly useful for
+  * A new -I option for the server causes it to write a PID file,
-    daemon mode (issue #120).
+    mostly useful for daemon mode (issue #120).
 
   * A --logfile argument can now force all output to go to a file,
     rather than to a file.  This is especially useful when running an
@@ -26,8 +26,9 @@ functionality in iperf 3.1.0, but not present in 3.0.11 or any earlier
     NetBSD (issue #248), Solaris (issue #175, issue #178, issue #180,
     issue #211), vxWorks (issue #268).
 
-  * A --udp-counters-64bit feature has been added to support very long
+  * A --udp-counters-64bit flag has been added to support very
-    UDP tests (issue #191).
+    long-running UDP tests, which could cause a counter to overflow
+    (issue #191).
 
   * A --cport option to specify the client-side port has been added
     (issue #207, issue #209, issue #239).
@@ -38,7 +39,9 @@ functionality in iperf 3.1.0, but not present in 3.0.11 or any earlier
   * A potential crash in the iperf3 server has been fixed (issue #257,
     issue #258).
 
-* Developer-visible changes
+  * Many miscellaneous bug fixes.
+
+* Selected developer-visible changes
 
   * Consumers of libiperf can now get the JSON output for a
     just-completed test (issue #147).