encode an estring into another estring for transmission inside XML data
int firestring_estr_xml_encode(struct firestring_estr_t *destination, struct firestring_estr_t *source)
firestring_estr_xml_encode() encodes the contents of
by escaping characters that might trigger XML processing into
provided that there is room in
The minimum required space in destination is the length of source * 6.
0 if the string was encoded successfully; 1 if there was insufficient space in
for the encoding to occur.