Upgrade Recast to 0.4.8 to fix options.writeback bug.

Bug introduced by: benjamn/recast@e913b22f8f
Bug fixed by: benjamn/recast@170e18091e
(cherry picked from commit 2383fd8)

Author: benjamn

package.json

@@ -38,7 +38,7 @@
     "base62": "~0.1.1",
     "commoner": "~0.7.0",
     "esprima": "git://github.com/facebook/esprima#fb-harmony",
-    "recast": "~0.4.5",
+    "recast": "~0.4.8",
     "source-map": "~0.1.22"
   },
   "devDependencies": {