fuel/core — pull request #1457 by benharold (2013-05-31 21:44:21+00:00)
Title: replace non-alphanum characters before checking for numeric keys

As discussed in a previous pull request: https://github.com/fuel/core/pull/1405 as well as forum post: http://fuelphp.com/forums/discussion/12119/best-way-to-avoid-invalid-xml-formatting-in-api-output