Fix typo in ResultSet::_rs()

Fix typo in ResultSet::_rs()
Use ZOOM::Record->_new() instead of "indirect object" syntax (why?!)
Connection::option_set() replaced by option() which gets and sets.
Add _rec(), render() and raw() methods to ZOOM::Record.
Add destroy() methods for Connection and ResultSet.
Attempts to use destroy()ed Connection and ResultSet cause die()
Clearer commentary on naming conventions.