special character in strings can break RPCs

[dcornejo]

passing a string containing a "<" character will break the RPC parsing:

Apr 17 10:08:53 ng1 clixon_backend[31155]: clixon_xml_parseerror: 188: XML error: xml_parse: line 0: syntax error: at or before: .

It appears that the character is not escaped and confuses the RPC parser. It is possible to require the sender to encode and receiver to decode the data, but this would not protect against a malicious injection.

[olofhagsand]

Quite extensive changes. Should have been fixed long time ago,.... There may still remain corner-cases. Please report if detected.