Genie:  Pass raw node* to StreamHandle constructor
Genie:  Accept only raw node* in StreamHandle ctor
Genie:  Avoid GetSimpleDeviceHandle() in Process()

Just resolve the pathname and open it.  We don't want the added coupling
of an extra interface.
Genie:  Pass the node to GetSimpleDeviceHandle()
Genie:  Merge Devices unit into IO/SimpleDevice
Genie:  Replace IOPtr in SimpleDevice.hh
Genie:  Hide SimpleDeviceHandle details
Genie:  Throw within findDevice() and return ref
Genie:  Pass node to SimpleDeviceHandle ctor
Genie:  Axe SimpleDeviceHandle::GetFile()
Merge branch 'simple-device-GetFile' into simple-device-refactor
Merge branch 'simple-device-refactor'