cmogstored 0.5.0

* I/O utilization is now reported correctly when multiple
  MogileFS devices share the same local filesystem

* attempt to reduce client-side syscalls on low-latency networks
  with TCP_NOPUSH/TCP_CORK

* remove a tiny chance of starvation when sharing work between threads
  while improving theoretical fairness

* minor code cleanups and gnulib updates

* acceptor threads push directly into the event queue to avoid
  poorly-defined TCP_DEFER_ACCEPT/accept filter semantics

* acceptor threads no longer touch the FS, so they are now scaled
  to CPU count, not filesystem count

* absolute URIs are now supported in HTTP/1.1 requests