Add VSCode run-and-debug config for building the site

This makes it easy to use the vscode debugger for the build process

Author: fredemmott

.vscode/launch.json

@@ -0,0 +1,14 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Build",
+      "type": "hhvm",
+      "request": "launch",
+      "script": "${workspaceFolder}/bin/build.php"
+    }
+  ]
+}