[npm] Use stacktrace-parser version that lists io.js under "engines"

stacktrace-parser used to list only Node 0.10 under its list of supported engines. This new version includes Node 1.x and 2.x (i.e. io.js) as well, which addresses the warning.

Test Plan: Run `npm install` under io.js -- no more warnings about a mismatched Node version.

Author: ide

package.json

@@ -63,7 +63,7 @@
     "rebound": "^0.0.12",
     "sane": "^1.1.2",
     "source-map": "0.1.31",
-    "stacktrace-parser": "frantic/stacktrace-parser#493c5e5638",
+    "stacktrace-parser": "ide/stacktrace-parser#iojs",
     "uglify-js": "~2.4.16",
     "underscore": "1.7.0",
     "worker-farm": "^1.3.1",