Add integration tests for fetch/slurp, make powershell fetch/slurp work as close as possible to existing fetch/slurp modules.

lib/ansible/module_utils/powershell.ps1

@@ -62,5 +62,5 @@ Function Fail-Json($obj, $message)
     Set-Attr $obj "msg" $message
     Set-Attr $obj "failed" $true
     echo $obj | ConvertTo-Json
-    Exit
+    Exit 1
 }