Adding nexmo sms to the select

Just adding nexmo as an option to the select drop down.

This is a follow up to work done on Issue #170

src/templates/default/module/config/config.tpl.html

@@ -200,6 +200,7 @@
 						<option value="freemobilesms" {{ sms_selected_freemobilesms|raw }}>{{ label_sms_gateway_freemobilesms }}</option>
 						<option value="clicksend" {{ sms_selected_clicksend|raw }}>{{ label_sms_gateway_clicksend }}</option>
 						<option value="smsgw" {{ sms_selected_smsgw|raw }}>{{ label_sms_gateway_smsgw }}</option>
+						<option value="nexmo" {{ sms_selected_nexmo|raw }}>{{ label_sms_gateway_nexmo }}</option>
                       </select>
                 </div>
             </div>