SecurityServer is a work in progress.

Important items that we know need to be cleaned up for Cheetah:
Sort out which memory allocations should be sensitive, and make them so.
Use CssmAutoData & friends copiously
Replace MIG server loop with a custom version and integrate deferred
  allocation release and timed events.

Questionable for Cheetah (not important enough/too big?):
Multi-threading the SecurityServer main request loop. This would require
  thread-safing the entire server core, which right now it probably isn't.

Major missing features (for future consideration):
ACL-related callbacks (+ possibly other callbacks)
  This would require IPC support that makes the IPC path asynchronous
  (or else requires interesting step dancing on the client side).
  It's not trivial, but eventually we'll have to do it. At least the
  data structure transports are already pretty much in place.
