UP-4205 CVE-2014-4172 Add request parameter sanitizing filter to 4.1-patches.

This is #405 except against the `4.1` patches branch rather than against the `4.0` patches branch.

Please review at #405 instead.

This Pull Request captures the intent to apply these same changes to the 4.1 patches branch for the 4.1.1 release and is the intended mechanism for actually applying those changes to the branch.