Making progress toward a release

Documented headers.lua
Update copyright date everywhere
Remove RCSID from files
Move version back to 2.1 rather than 2.1.1
Fixed url package to support ipv6 hosts
Changed "domain" to "family" in tcp and udp structures
Implemented getfamily methods

doc/socket.html

@@ -112,6 +112,29 @@ t = socket.gettime()
 print(socket.gettime() - t .. " seconds elapsed")
 </pre>
 
+<!-- socket.headers ++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
+
+<p class=name id="headers.canonic">
+socket.headers.<b>canonic</b></p>
+
+<p> The <tt>socket.headers.canonic</tt> table 
+is used by the HTTP and SMTP modules to translate from 
+lowercase field names back into their canonic 
+capitalization. When a lowercase field name exists as a key
+in this table, the associated value is substituted in
+whenever the field name is sent out.
+</p>
+
+<p> 
+You can obtain the <tt>headers</tt> namespace if case run-time
+modifications are required by running:
+</p>
+
+<pre class=example>
+-- loads the headers module 
+local headers = require("headers")
+</pre>
+
 <!-- newtry +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
 
 <p class=name id=newtry>