- new method for ::xotcl::Object mset: set a series of instance
variables via the provided attribute value list (as e.g. returned by
[array get], [ns_set array], ...
- implement the prepared statement handling within the scope of
a "db_with_handle", to make sure, the prepare and the subsequent
command are using the same handle (and therefore session).
- use for prepared statement caching the result of [ns_db session_id]
when available
- bump version to 0.155