Adding support for getting MogileFS devices

each host of MogileFS can have a number of devices, each one with
different space utilization, state, status etc...

this adds a command to bring the attributes provided by MogileFS
Started to merge @kazabubu's device status implementation
Changed logging level for bad formatting in the device status response
Tightened up some naming/terminology
Check parameter names
Removed response extraction for getDeviceStatuses into the tracker
Further refactored getDeviceStatuses response handling into an operation
Added a test for the get device status operation.
Added source headers.
Test for getDeviceStatuses tracker implementation
Command test
Declare IOException on getDeviceStatuses
Source header
Changed credit in changelog
Only need to lowercase once
Moved lowercase operation
Fixed InetSocketAddress mocking issue