Add PowerShell version of checkout-deps script for Windows (NPOTB).

tools/checkout-deps.ps1

@@ -0,0 +1,81 @@
+<#
+.SYNOPSIS
+    Downloads dependencies for compiling SourceMod.
+.PARAMETER SDKs
+    List of HL2SDK branch names to downloads.
+#>
+
+[CmdletBinding()]
+param(
+    [string[]]$SDKs = @(
+        'csgo',
+        'hl2dm',
+        'nucleardawn',
+        'l4d2',
+        'dods',
+        'l4d',
+        'css',
+        'tf2',
+        'insurgency',
+        'sdk2013',
+        'dota'
+        )
+)
+
+Function Checkout-Repo
+{
+    param(
+        [Parameter(Mandatory=$true)][string]$Name,
+        [Parameter(Mandatory=$true)][string]$Branch,
+        [Parameter(Mandatory=$true)][string]$Repo,
+        [string]$Origin
+    )
+
+    If (-not (Test-Path $Name -PathType Container))
+    {
+        & git clone $Repo -b $Branch $Name 2>&1 | Write-Host
+        If ($Origin)
+        {
+            Set-Location $Name
+            & git  remote rm origin 2>&1 | Write-Host
+            & git remote add origin $Origin 2>&1 | Write-Host
+            Set-Location ..
+        }
+    }
+    Else
+    {
+        Set-Location $Name
+        & git checkout $Branch 2>&1 | Write-Host
+        & git pull origin $Branch 2>&1 | Write-Host
+        Set-Location ..
+    }
+}
+
+if (-not (Test-Path "sourcemod" -PathType Container))
+{
+    Write-Error "Could not find a SourceMod repository; make sure you aren't running this script inside it."
+    Exit 1
+}
+
+Checkout-Repo -Name "mmsource-1.10" -Branch "1.10-dev" -Repo "https://github.com/alliedmodders/metamod-source.git"
+
+if (-not (Test-Path "hl2sdk-proxy-repo" -PathType Container))
+{
+    & git clone --mirror https://github.com/alliedmodders/hl2sdk hl2sdk-proxy-repo 2>&1 | Write-Host
+}
+else
+{
+    Set-Location hl2sdk-proxy-repo
+    & git fetch 2>&1 | Write-Host
+    Set-Location ..
+}
+
+$SDKS | % {
+    Checkout-Repo -Name "hl2sdk-$_" -Branch $_ "hl2sdk-proxy-repo" -Repo "https://github.com/alliedmodders/hl2sdk.git"
+}
+
+Checkout-Repo -Name "ambuild" -Branch "master" -Repo "https://github.com/alliedmodders/ambuild.git"
+Set-Location ambuild
+& python setup.py install
+
+Set-Location ..