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.

library/server/ewsgi/connectors/standalone/lib/httpd/concurrency/scoop/httpd_request_handler.e

@@ -25,20 +25,27 @@ feature {CONCURRENT_POOL, HTTPD_CONNECTION_HANDLER_I} -- Basic operation
 	release
 			-- <Precursor>
 		local
-			d: STRING
+			d: detachable STRING
 		do
-			if attached internal_client_socket as l_socket then
-				d := l_socket.descriptor.out
-			else
-				d := "N/A"
-			end
 			debug ("dbglog")
+				if 
+					attached internal_client_socket as l_socket and then
+					l_socket.descriptor_available
+				then
+					d := l_socket.descriptor.out
+				else
+					d := "N/A"
+				end
 				dbglog (generator + ".release: ENTER {" + d + "}")
 			end
 			Precursor {HTTPD_REQUEST_HANDLER_I}
 			release_pool_item
 			debug ("dbglog")
-				dbglog (generator + ".release: LEAVE {" + d + "}")
+				if d /= Void then
+					dbglog (generator + ".release: LEAVE {" + d + "}")
+				else
+					dbglog (generator + ".release: LEAVE {N/A}")
+				end
 			end
 		end
 

library/server/ewsgi/connectors/standalone/lib/httpd/concurrency/thread/httpd_request_handler.e

@@ -18,21 +18,28 @@ inherit
 feature {HTTPD_CONNECTION_HANDLER_I} -- Basic operation		
 
 	release
+			-- <Precursor>
 		local
-			d: STRING
+			d: detachable STRING
 		do
-			-- FIXME: for log purpose
-			if attached internal_client_socket as l_socket then
-				d := l_socket.descriptor.out
-			else
-				d := "N/A"
-			end
 			debug ("dbglog")
+				if 
+					attached internal_client_socket as l_socket and then
+					l_socket.descriptor_available
+				then
+					d := l_socket.descriptor.out
+				else
+					d := "N/A"
+				end
 				dbglog (generator + ".release: ENTER {" + d + "}")
 			end
 			Precursor {HTTPD_REQUEST_HANDLER_I}
 			debug ("dbglog")
-				dbglog (generator + ".release: LEAVE {" + d + "}")
+				if d /= Void then
+					dbglog (generator + ".release: LEAVE {" + d + "}")
+				else
+					dbglog (generator + ".release: LEAVE {N/A}")
+				end
 			end
 		end