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_contact.tpl

@@ -0,0 +1,25 @@
+<div class="contact-box clearfix">
+    <h1>Contact us!</h1>
+    <form method="post" action="{$site_url/}contact" id="contact-form">
+        <label for="name">Name: <span class="required">*</span></label>
+        <input type="text" id="name" name="name" value="{$name/}" required="required" autofocus="autofocus" />
+         
+        <label for="email">Email Address: <span class="required">*</span></label>
+        <input type="email" id="email" name="email" value="{$email/}" required="required" />
+         
+        <label for="message">Message: <span class="required">*</span></label>
+        <textarea id="message" name="message" required="required" data-minlength="20" minlength="20" >{$message/}</textarea>
+		{unless isempty="$recaptcha_site_key"}
+        <div class="g-recaptcha" data-sitekey="{$recaptcha_site_key/}"></div>
+        <br/>
+		{/unless}
+        <input type="submit" value="Send" class="submit-button" />
+        <p class="req-field-desc"><span class="required">*</span> indicates a required field</p>
+    </form>
+    {unless isempty="$error_response"}
+        <ul class="message error">
+			{foreach item="item" from="$error_response"}<li class="info">{$item/}</li>{/foreach}
+        </ul>
+        <div class="notice"> Try again later </div>
+    {/unless}        
+</div>