- (WGI|WSF)_RESPONSE(*) renamed write_headers_string as write_header_text

- HTTP_HEADER.string does not have the ending CRLFCRLF .. but just CRLF
- WGI_RESPONSE.write_header_text has the responsibility to handle the last blank line CRLF (separating the header from the message)
- HTTP_HEADER.string does not set anymore a default content type as text/html
- added WGI_RESPONSE.write_header_lines (ITERABLE [TUPLE [name,value: READABLE_STRING_8]] mainly as an helper method,
   this way the WGI user does not have to know about the CRLF end of line

library/server/ewsgi/specification/response/wgi_response.e

@@ -68,7 +68,22 @@ feature -- Status setting
 
 feature -- Header output operation
 
-	write_headers (a_headers: READABLE_STRING_8)
+	write_header_text (a_text: READABLE_STRING_8)
+			-- Write http header string `a_text'
+			-- It should not contain the ending CR LF CR LF
+			-- since it is the duty of `write_header_text' to write it.
+		require
+			a_text_does_not_has_ending_crlf_crlf: a_text.count > 4 implies not a_text.substring (a_text.count - 4, a_text.count).same_string ("%R%N%R%N")
+			status_set: status_is_set
+			header_not_committed: not header_committed
+		deferred
+		ensure
+			status_set: status_is_set
+			header_committed: header_committed
+			message_writable: message_writable
+		end
+
+	write_header_lines (a_lines: ITERABLE [TUPLE [name: READABLE_STRING_8; value: READABLE_STRING_8]])
 		require
 			status_set: status_is_set
 			header_not_committed: not header_committed