Update SMP task list
(1) Note that Alfred has completed "simple" locking for pipes: this
includes small reads and writes that don't trigger VM optimizations, and the SIGIO, fsetown(), and related inter-process evil for pipes. Another item off the check-list for 5.0-RELEASE.
(2) Create two new tasks: sigio/setfown/... components of pipes. Mark
this as WIP, and assign to Alfred. Create a VM optimizations pipe task without an owner: we'll probably get this for free as part of fine-grained VM locking when that happens.