#79 Remove node locking

[Jay Bonci]

We can remove the primary traits of the nodelocking,
because with transactional support inside of the
nodebase, the functionality it was meant to represent is
obsolete.

This includes "lock_user" and "locktime" as needs in
the main node table. We'd need to redump the ecore
and nodeballs, but it would make stuff smaller.

And we'd suck the marrow out of life.

[chromatic]

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Which transactional support in nodebase handles this?

If this is removed, we need to write and distribute a script
to remove the node fields for people migrating from older
versions. It could be as simple as overriding the
appropriate getNodeKeepKeys().