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.
since app_name is declared as STRING ... i.e STRING_8, and not the unicode STRING_32
for now, let's assume we store as UTF_8

later, we may either accept only ascii app_name, or unicode name, but we'll see that later.

unicode support is not always trivial.

remember that in Eiffel
STRING_8 can be used to store ASCII, or any 8bit encoding, and we can precise in comment this is using UTF-8 for instance.
or just use STRING_32 .. that store unicode string (UTF-32).