Converted code to void-safety and use better Eiffel feature naming.

Changed feature names to match Eiffel naming conventions.
Updated to use WSF_PAGE_RESPONSE which compute among other the Content-Length http header.
using the WSF_PAGE_RESPONSE, it computes itself the Content-Length http header , which is important in http protocol.
In previous case, this Content-Length was not send, and thus may lead to unexpected behavior.