Make sure we handle longs.

Unforutnaly, MongoDB has a 64-bit limit. Sigh. We can later add a custom
serializer if we really have to.
Bump the version as well.
Bug: When a sub-document object is changed and then the main object is
removed, the removed object would re-appear, since the sub-document object
was still registered as changed and caused a write undoing the removal. The
issue was fixed by removing all registered sub-document objects as well from
the list during removal.
Whitespace.
Restore the state of the parent on aborts with persistent subobjects.
fix a corner case when _p_jar was not handed down
Fix Adam's fix. :-)
bump version number.
Allow to pass class to load() explicitly

This will allow to skip expensive class resolution, when class is
already known.