#2 Add object creation security

[Chris Winters]

In rethink of SPOPS (coming this fall), add the ability
to ask the security object for *class-level* security,
which would be used to indicate whether a user/group
could create an object or not.

Previously we relied on the application to do this, but
there's no reason that we can't just use a specific
object ID (e.g., '-1') to indicate that the security
belongs to the class. The normal security checks would
apply.

Thanks to Eric Veldhuyzen for the idea.