Ensure that PATH_INFO and REQUEST_URI are following the CGI specifications:

- PATH_INFO is percent decoded but still utf-8 encoded,
  this is available via WGI.path_info and WSF_REQUEST.utf_8_path_info.
- Added WSF_REQUEST.percent_encoded_path_info
- and WSF_REQUEST.path_info remains the unicode value for PATH_INFO

Added cgi_variables: WGI_REQUEST_CGI_VARIABLES to have a simple and quick view on CGI variables
Added execution_variables to be able to iterate on execution variables.
Added PERCENT_ENCODER.percent_decoded_utf_8_string
Improved the WSF_DEBUG_HANDLER to provide more information thanks to WSF_DEBUG_INFORMATION object.

library/text/encoder/src/percent_encoder.e

@@ -208,8 +208,15 @@ feature {NONE} -- Implementation: character encoding
 feature -- Percent decoding
 
 	percent_decoded_string (v: READABLE_STRING_GENERAL): STRING_32
-			-- Return the percent decoded string equivalent to the percent-encoded string `v'
-			--| Note that is `a_result' is a STRING_8, any Unicode character will be kept as UTF-8
+			-- Return the percent decoded unicode string equivalent to the percent-encoded string `v'
+		do
+			create Result.make (v.count)
+			append_percent_decoded_string_to (v, Result)
+		end
+
+	percent_decoded_utf_8_string (v: READABLE_STRING_GENERAL): STRING_8
+			-- Return the percent decoded UTF-8 string equivalent to the percent-encoded string `v'
+			--| Note that any Unicode character will be kept as UTF-8
 		do
 			create Result.make (v.count)
 			append_percent_decoded_string_to (v, Result)