Updated WGI specification to ease future migration to unicode support.

Use STRING_TABLE, and better interface of READABLE_STRING_GENERAL,
    this way the signature are more flexible for unicode keys.

    Note that for now, unicode environment variables are not correctly supported in WGI
    especially the value of the variables.
    Any layer on top of EWGSI suffers from the same issues.

Better exception handling

+ code cleaning

library/server/ewsgi/connectors/libfcgi/src/wgi_libfcgi_connector.e

@@ -55,7 +55,7 @@ feature -- Server
 
 feature -- Execution
 
-	process_fcgi_request (vars: HASH_TABLE [STRING, STRING]; a_input: like input; a_output: like output)
+	process_fcgi_request (vars: STRING_TABLE [READABLE_STRING_8]; a_input: like input; a_output: like output)
 		local
 			req: WGI_REQUEST_FROM_TABLE
 			res: detachable WGI_RESPONSE_STREAM
@@ -82,8 +82,10 @@ feature -- Execution
 				end
 			end
 		rescue
-			rescued := True
-			retry
+			if not rescued then
+				rescued := True
+				retry
+			end
 		end
 
 feature -- Input/Output