kgio 2.5.0 - a minor feature update

* Kgio::File.tryopen method added.  It is like File.open
  but won't raise exceptions.  The Kgio::File class includes
  Kgio::PipeMethods, so FIFOs opened through this get the
  kgio_* API.

* The kgio_wait_*able methods in Kgio::DefaultWaiters
  now accept an optional timeout argument.