added status setting in GW_RESPONSE
added a default implementation for write_status in OUTPUT_STREAM
(it should be moved away in the future)
removed any implementation from GW_REQUEST, and put it in GW_REQUEST_IMP
So this is really more flexible this way, and much easier to write application supporting CGI, FCGI, Nino and so on .. as demonstrated in hello_world
This is a first version, more will come later, mainly migrating from Eiffel Web Reloaded to this Eiffel Web Framework project.
