Update the current version of the library and add GitHub link

doc/site/index.htm

@@ -19,12 +19,24 @@
 <div class="links">
 <h3>Links</h3>
 <ul class="menu">
-<li><a href="http://sourceforge.net/projects/elfio/files/">Download</a> the source
-    distribution</li><br/>
+
+<li>Download the source distribution from
+<a href="http://sourceforge.net/projects/elfio/files/">SourceForge</a>
+or
+<a href="https://github.com/serge1/ELFIO/releases">GitHub</a>
+repositories
+</li><br/>
+
 <li>Read the <a href="elfio.pdf">Tutorial and User Manual</a></li><br/>
+
+<li>Visit the
+<a href="https://github.com/serge1/ELFIO">GitHub project page</a></li><br/>
+
 <li>Visit the
 <a href="http://sourceforge.net/projects/elfio/">SourceForge project page</a></li><br/>
+
 <li><a href="oldsite/index.htm">Old documentation</a> for outdated 1.0.3 version of the library</li><br/>
+
 <li>Send <a href="mailto:to_serge@users.sourceforge.net">feedback, comments, patches, etc.</a></li></br>
 </ul>
 </div>
@@ -42,14 +54,14 @@ and compilers.
 </p>
 <p>
 While the library is easy to use, some basic knowledge of the ELF binary format
-is required. Such Information can easily be found on the Web.
+is required. Such Information can be easily found on the Web.
 </p>
 <p>
-Current version of <em>ELFIO</em> library is 2.x and it is distributed under
+The current version of <em>ELFIO</em> library is 3.x and it is distributed under
 <a href="http://www.opensource.org/licenses/MIT">MIT License</a> conditions.
 </p>
 <p>
-Note for users of previous library versions 1.0.x: Version 2.x is not source
+Note for users of previous library versions 1.0.x: Version 3.x is not source
 compatible to earlier versions. Transition to the new library interface is
 straightforward though.
 </p>