Added script to easily enable VS dev mode

scripts/VSDevMode.ps1

@@ -0,0 +1,49 @@
+<#
+.SYNOPSIS
+Run this PowerShell script to enable dev mode and/or a custom script for the TypeScript language service, e.g.
+
+PS C:\> .\scripts\VSDevMode.ps1 -enableDevMode -tsScript C:\src\TypeScript\built\local\typescriptServices.js
+
+Note: If you get security errors, try running powershell as an Administrator and with the "-executionPolicy remoteSigned" switch
+
+.PARAMETER vsVersion
+Set to "12" for Dev12 (VS2013) or "14" (the default) for Dev14 (VS2015)
+
+.PARAMETER enableDevMode
+Pass this switch to enable attaching a debugger to the language service
+
+.PARAMETER tsScript
+The path to a custom language service script to use, e.g. "C:\src\TypeScript\built\local\typescriptServices.js"
+#>
+Param(
+    [int]$vsVersion = 14,
+    [switch]$enableDevMode,
+    [string]$tsScript
+)
+
+$vsRegKey = "HKCU:\Software\Microsoft\VisualStudio\${vsVersion}.0"
+$tsRegKey = "${vsRegKey}\TypeScriptLanguageService"
+
+if($enableDevMode -ne $true -and $tsScript -eq ""){
+    Throw "You must either enable language service debugging (-enableDevMode), set a custom script (-tsScript), or both"
+}
+
+if(!(Test-Path $vsRegKey)){
+    Throw "Visual Studio ${vsVersion} is not installed"
+}
+if(!(Test-Path $tsRegKey)){
+    # Create the TypeScript subkey if it doesn't exist
+    New-Item -path $tsRegKey
+}
+
+if($tsScript -ne ""){
+    if(!(Test-Path $tsScript)){
+        Throw "Could not locate the TypeScript language service script at ${tsScript}"
+    }
+    Set-ItemProperty -path $tsRegKey -name CustomTypeScriptServicesFileLocation -value "${tsScript}"
+    Write-Host "Enabled custom TypeScript language service at ${tsScript} for Dev${vsVersion}"
+}
+if($enableDevMode){
+    Set-ItemProperty -path $tsRegKey -name EnableDevMode -value 1
+    Write-Host "Enabled developer mode for Dev${vsVersion}"
+}