update CHANGES.html and RELEASE_NOTES

CHANGES.html

@@ -55,6 +55,11 @@ us a note on ns-developers mailing list.</p>
 
 <h2>New API:</h2>
 <ul>
+  <li>Data collection components have been added in the src/stats module.
+      Data collection includes a Probe class that attaches to ns-3 trace
+      sources to filter their output, and two Aggregator classes for 
+      marshaling probed data into text files or gnuplot plots.  The ns-3
+      tutorial has been extended to illustrate basic functionality. </li>
   <li>Time attributes can now be bounded.  See attribute-test-suite.cc
       for an example.</li>
   <li>New generic hash function interface.  Two hash functions are provided:

RELEASE_NOTES

@@ -23,7 +23,9 @@ New user-visible features
 -------------------------
 - Time attributes can now be bounded.  See attribute-test-suite.cc for an
   example.
-- IPv6 addrss class 2001:db8::/32 is now dropped by routers (RFC 3849).
+- Data collection components have been added to the stats module.  These
+  components can be used to generate time series data in files and plots.
+- IPv6 address class 2001:db8::/32 is now dropped by routers (RFC 3849).
 - New generic hash function interface.  Two hash functions are provided:
   murmur3 (default), and the venerable FNV1a.  See the Hash Functions
   section in the Manual.