Add support for split 32/64 bit build trees.

While also retaining support for a single architecture directly in the
`build` directory.

scripts/helpers.js

@@ -0,0 +1,24 @@
+// Helper functions shared across scripts.
+var path = require('path');
+var fs = require('fs');
+
+function fileExists(file_path) {
+    try {
+        // Query the entry
+        stats = fs.lstatSync(file_path);
+
+        // Is it a directory?
+        if (stats.isFile()) {
+            return true;
+        }
+    } catch (e) {}
+
+    return false;
+}
+
+function isMultiArch(root_path) {
+    return fileExists(path.join(root_path, 'build', '64', 'Release', 'loot64.dll'));
+}
+
+module.exports.fileExists = fileExists;
+module.exports.isMultiArch = isMultiArch;