v0.7.0

The container's processes and a kernel's are one pid space. A minor
release: the exported surface gained installProcessIdAllocator and
RunOptions.process.

• installProcessIdAllocator(allocate) (container owner): every process
  number is taken from the host's own pid counter from then on, so a guest's
  process.pid, its child's process.ppid and the kernel's
  /proc/<pid>/stat name one process, and no number is given twice. A number
  still held is passed over.
• RunOptions.process (for runNode): { pid, ppid } a host already gave
  the run, a kernel's for a node its shell exec'd. The run is that process,
  its parent the host's, which the registry need not hold.