Update server code integration for QtWebApp 1.7.11

- Adapt server code for QtWebapp namespace 'stefanfrings'
- Implement custom modifications needed by v1 controller
  via template engine
- Unify iphone and ipad templates

YACReaderLibrary/server/controllers/v2/errorcontroller_v2.cpp

@@ -3,6 +3,9 @@
 #include "template.h"
 #include "../static.h"
 
+using stefanfrings::HttpRequest;
+using stefanfrings::HttpResponse;
+
 ErrorControllerV2::ErrorControllerV2(int errorCode)
     : error(errorCode)
 {