Capitalize node.buffer-option

Since webpack 1.5 the casing of `buffer` has been changed to `Buffer` (because it refers to the global `Buffer` variable)

Author: jhnns

webpack.config.js

@@ -28,7 +28,7 @@ module.exports = {
   },
 
   node: {
-    buffer: false
+    Buffer: false
   },
 
   plugins: plugins