add support for windows 2016 ami import with vbox

windows_2016_ami.json

+{
+  "builders": [
+   {
+      "boot_wait": "2m",
+      "communicator": "winrm",
+      "disk_size": "{{user `disk_size`}}",
+      "floppy_files": [
+        "{{user `autounattend`}}",
+        "./scripts/disable-screensaver.ps1",
+        "./scripts/disable-winrm.ps1",
+        "./scripts/enable-winrm.ps1",
+        "./scripts/microsoft-updates.bat",
+        "./scripts/win-updates.ps1",
+        "./scripts/unattend.xml",
+        "./scripts/sysprep.bat"
+      ],
+      "guest_additions_mode": "disable",
+      "guest_os_type": "Windows2016_64",
+      "headless": "{{user `headless`}}",
+      "iso_checksum": "{{user `iso_checksum`}}",
+      "iso_checksum_type": "{{user `iso_checksum_type`}}",
+      "iso_url": "{{user `iso_url`}}",
+      "shutdown_command": "a:/sysprep.bat",
+      "type": "virtualbox-iso",
+      "vboxmanage": [
+        [
+          "modifyvm",
+          "{{.Name}}",
+          "--memory",
+          "2048"
+        ],
+        [
+          "modifyvm",
+          "{{.Name}}",
+          "--cpus",
+          "2"
+        ]
+      ],
+      "vm_name": "WindowsServer2016",
+      "winrm_password": "vagrant",
+      "winrm_timeout": "{{user `winrm_timeout`}}",
+      "winrm_username": "vagrant"
+    }
+  ],
+  "post-processors": [
+    {
+      "keep_input_artifact": false,
+      "output": "windows_2016_{{.Provider}}.box",
+      "type": "vagrant",
+      "vagrantfile_template": "vagrantfile-windows_2016.template"
+    },
+    {
+      "type": "amazon-import",
+      "only": ["virtualbox-iso"],
+      "access_key": "",
+      "secret_key": "",
+      "region": "",
+      "s3_bucket_name": "{{user `aws_s3_bucket_name`}}",
+      "keep_input_artifact": false,
+      "license_type": "BYOL",
+      "tags": 
+      {
+      "Description": "packer-windows amazon-import {{timestamp}}"
+      }
+    }
+  ],
+  "provisioners": [
+    {
+      "execute_command": "{{ .Vars }} cmd /c \"{{ .Path }}\"",
+      "scripts": [
+        "./scripts/vm-guest-tools.bat",
+        "./scripts/enable-rdp.bat"
+      ],
+      "type": "windows-shell"
+    },
+    {
+      "scripts": [
+        "./scripts/debloat-windows.ps1"
+      ],
+      "type": "powershell"
+    },
+    {
+      "restart_timeout": "{{user `restart_timeout`}}",
+      "type": "windows-restart"
+    },
+    {
+      "execute_command": "{{ .Vars }} cmd /c \"{{ .Path }}\"",
+      "scripts": [
+        "./scripts/pin-powershell.bat",
+        "./scripts/set-winrm-automatic.bat",
+        "./scripts/uac-enable.bat",
+        "./scripts/compile-dotnet-assemblies.bat",
+        "./scripts/dis-updates.bat",
+        "./scripts/compact.bat"
+      ],
+      "type": "windows-shell"
+    },
+    {
+    "type": "powershell",
+    "inline": [ "C:/ProgramData/Amazon/EC2-Windows/Launch/Scripts/InitializeInstance.ps1 -Schedule",
+                "C:/ProgramData/Amazon/EC2-Windows/Launch/Scripts/SysprepInstance.ps1 -NoShutdown"
+              ]
+    }
+    ],
+  "variables": {
+    "autounattend": "./answer_files/2016/Autounattend.xml",
+    "disk_size": "61440",
+    "disk_type_id": "1",
+    "headless": "false",
+    "hyperv_switchname": "{{env `hyperv_switchname`}}",
+    "iso_checksum": "70721288BBCDFE3239D8F8C0FAE55F1F",
+    "iso_checksum_type": "md5",
+    "iso_url": "https://software-download.microsoft.com/download/pr/Windows_Server_2016_Datacenter_EVAL_en-us_14393_refresh.ISO",
+    "restart_timeout": "5m",
+    "winrm_timeout": "4h",
+    "aws_s3_bucket_name": "{{env `AWS_S3_BUCKET`}}"
+  }
+}
+