add support for detecting implementation of lockable

Signed-off-by: Mattias Andrée <maandree@operamail.com>
interface_inheritance in copying and moving

Signed-off-by: Mattias Andrée <maandree@operamail.com>
event handler pointer fix

Signed-off-by: Mattias Andrée <maandree@operamail.com>
event handler pointer fix for basic senario

Signed-off-by: Mattias Andrée <maandree@operamail.com>