BUILD-QUERY (&REST FIELD-VALUE)
RETURN: A formated string containing the field=value&field=value… EXAMPLE: (build-query :first-name "john" :surname "doe") --> "first%2Dname=john&surname=doe"
QUERY-ARGUMENT (NAME QUERY-ARGUMENTS)
RETURN: The value of the QUERY-STRING argument named NAME.
RETURN: A string where the spaces are replaced by '+' and other unsavory characters are replaced by %HL sequences.
RETURN: the QUERY-ARGUMENTS, a list of lists (variable . value) found in the HTML CGI QUERY-STRING.
RETURN: A string where the + are replaced by spaces and the %HL are replaced by the caracter whose code is HL in hexadecimal.