Added CMS_STRING_EXPANDER.

For now with basic implementation.
  It will be improved later

Added SEO related attribute in CMS_RESPONSE.
Added improved Contact module.
Added basic SEO module.

examples/demo/site/modules/contact/templates/block_post_contact.tpl

@@ -0,0 +1,15 @@
+<div class="contact-box">
+{if condition="$has_error"}
+<div class="message error">
+		<strong>Internal Server Error <small>Error 500</small></strong>
+		<p>The page you requested could not be served because the server is down,
+		either contact the webmaster or try again. 
+		Use your browser's <strong>Back</strong> button to navigate to the page you came from.</p>
+		<p><strong>Or you could just press this link:</strong> <a href="{$site_url/}" itemprop="home" rel="home">Take Me Home</a></p> 
+</div>
+{/if}
+{unless condition="$has_error"}
+<p class="message success">Thank you for contacting the Eiffel Programming Language community.<br/>
+We will get back to you promptly on your contact request.</p>	
+{/unless}
+</div>