Update the restbuck_client, still work in progress.

Update restbuck_server, remove unused class in inherit.
Update libcurl_http_client_request, to parse context headers before the
execution.
Update wgi_input_stream, commented precondition.

library/server/ewsgi/src/wgi_input_stream.e

@@ -27,7 +27,7 @@ feature -- Input
 	read_string (nb: INTEGER)
 		require
 			is_open_read: is_open_read
-			not_end_of_input: not end_of_input
+--			not_end_of_input: not end_of_input
 			nb_large_enough: nb > 0
 		deferred
 		ensure