userspace: automatic resource release framework

An object's set of permissions is now also used as a form
of reference counting. If an object's permission bitmap gets
completely cleared, it is now possible to specify object type
specific cleanup functions to be implicitly called.

Currently no objects are enabled yet. Forthcoming patches
will do this on a per object basis.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>