Support for multi-domain forest

[bpfoley45]

Running this tool with a user in the root domain of the forest works as expected. I have experienced the following failures:

• Specifying a user in a child domain
• setting the -domain param to a child domain with a child domain user
  Error:

[Get-AttrForADObject] User not found.
At B:\Invoke-ACLPwn.ps1:109 char:9
+         throw '[Get-AttrForADObject] User not found.'
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: ([Get-AttrForADObject] User not found.:String) [], RuntimeException
    + FullyQualifiedErrorId : [Get-AttrForADObject] User not found.