return owner for files on windows

[chris-rock]

This PR implements the owner methods for file/directory on Windows platforms. Once this is done, you can read our the owner via InSpec:

  describe directory('C:/opscode/chef') do
    its('owner') { should cmp 'NT AUTHORITY\SYSTEM'}
  end
  describe directory('C:/opscode/chef') do
    it { should be_owned_by 'NT AUTHORITY\SYSTEM' }
  end
  describe directory('C:/notthere') do
    its('owner') { should eq nil}
  end

[ksubrama]

If you just want the owner, you can just return stdout from Get-Acl '#{@spath}' | select -expand Owner

[chris-rock]

Uh, nice, lets use that instead.

[chris-rock]

Thanks @ksubrama for the tip, that made the implementation much easier

[chris-rock]

I am going to ignore the travis test for fedora, since this is combination of docker and travis.