Upgrade node to 6.3.1 (#966)

### Notable changes

* **buffer**:
  * Improve performance of Buffer.from(str, 'hex') and Buffer#write(str, 'hex'). (Christopher Jeffrey) [#7602](nodejs/node#7602)
  * Fix creating from zero-length ArrayBuffer. (Ingvar Stepanyan) [#7176](nodejs/node#7176)
* **deps**:
  * Upgrade to V8 5.0.71.xx. (Ben Noordhuis) [#7531](nodejs/node#7531)
  * Backport V8 instanceof bugfix (Franziska Hinkelmann) [#7638](nodejs/node#7638)
* **repl**: Fix issue with function redeclaration. (Prince J Wesley) [#7794](nodejs/node#7794)
* **util**: Fix inspecting of boxed symbols. (Anna Henningsen) [#7641](nodejs/node#7641)

bucket/nodejs.json

@@ -1,15 +1,15 @@
 {
     "homepage": "http://nodejs.org",
-    "version": "6.3.0",
+    "version": "6.3.1",
     "license": "MIT",
     "architecture": {
         "64bit": {
-            "url": "https://nodejs.org/dist/v6.3.0/node-v6.3.0-x64.msi",
-            "hash": "ec3fdc5e383948c68a2fa762be548ea18e83710c1b4af013b1b687faacfab274"
+            "url": "https://nodejs.org/dist/v6.3.1/node-v6.3.1-x64.msi",
+            "hash": "d41bb2d45bbd2dde7539c7c7e4f80865979f0bb15e6af0e7ee9460d9ad47c8ec"
         },
         "32bit": {
-            "url": "https://nodejs.org/dist/v6.3.0/node-v6.3.0-x86.msi",
-            "hash": "d838594fe4d3de0ec8265d742e7d3400a0e7c0c1d29df490f1f9c3af4639469d"
+            "url": "https://nodejs.org/dist/v6.3.1/node-v6.3.1-x86.msi",
+            "hash": "ed6c7ef60a0d04bfc5f766b7886c5f5dd3c79041bd2a00df6832fb416237f976"
         }
     },
     "env_add_path": "nodejs",