Release Name: 0.6.1

Notes:
* Added host_id method to Windows
* Bug fix in ip_addr method for Windows


Changes:
* Added the host_id method for Windows, which just returns the MAC address.
* Fixed an issue in the Host.ip_addr method for MS Windows where multiple ip
  addresses might not be handled properly. Thanks go to Murmansk Manny for the
  spot and patch.
* Updated the gemspec to include all .c and .h files now so that it should
  successfully build and install on all Unix platforms.
* Rakefile fix for MS Windows for the install task.
* The test file is now "test_sys_host.rb".