start working on Entity objects. added Entity* classes.
initial implementation of Entity classes. mostly copied from wsCore,
but only the ones that seems to be most important.
$_model *must* be set in Entity classes.
use new EntityInterface. moved getRecord to newEntity.
deleted obsolete interface (now EntityInterface).
set id_type as not necessary; maybe set based on the data in the future.
fetch sets class/object type.