Fixed SSL support on the httpd component, and also on the EiffelWeb standalone connector.

- the standalone connector support for SSL, is using certicate files for now (no in-memory support).
  - to enable ssl support, set ecf variable `httpd_ssl_enabled=true`.
  - added the `simple_ssl` example to demonstrate how to have standalone ssl server.
    (be careful when using EiffelNet SSL and the http_client library, disable the libcurl
      via ecf variable `libcurl_http_client_disabled=true` )

Added support for recv timeout to the EiffelWeb standalone connector.
  - made EiffelWeb compilable with 16.05 and upcoming 16.11.
    Done via ecfs condition on version to accept EiffelNet with recv_timeout (from 16.11), and without (until 16.05).
  - adding recv timeout prevents server to hang for ever if a client wait too long to send data.

Updated various comments.

examples/simple_ssl/application_execution.e

@@ -0,0 +1,41 @@
+note
+	description : "simple application execution"
+	date        : "$Date$"
+	revision    : "$Revision$"
+
+class
+	APPLICATION_EXECUTION
+
+inherit
+	WSF_EXECUTION
+
+create
+	make
+
+feature -- Basic operations
+
+	execute
+		local
+			s: STRING
+			dt: HTTP_DATE
+ 		do
+ 			-- To send a response we need to setup, the status code and
+ 			-- the response headers.
+ 			s := "Hello World!"
+			create dt.make_now_utc
+			s.append (" (UTC time is " + dt.rfc850_string + ").")
+			if request.is_https then
+				s.append ("<p>This is a secured connection! (https)</p>%N")
+			end
+
+			response.put_header ({HTTP_STATUS_CODE}.ok, <<["Content-Type", "text/html"], ["Content-Length", s.count.out]>>)
+			response.set_status_code ({HTTP_STATUS_CODE}.ok)
+			response.header.put_content_type_text_html
+			response.header.put_content_length (s.count)
+			if attached request.http_connection as l_connection and then l_connection.is_case_insensitive_equal_general ("keep-alive") then
+				response.header.put_header_key_value ("Connection", "keep-alive")
+			end
+			response.put_string (s)
+		end
+
+end