Fix bug #9966 ([CEF 2171] JSLint doesn't work)

Fix bug #9966 - Switch to a private fork of JSLint with the bug fix cherry-picked in so we're not stuck upgrading to a much newer JSLint which has the fix but is significantly stricter / less configurable.

Note: you must run `git submodule sync` after syncing to this change, in order for the submodule URI change to take effect.

Here's a diff of the actual change in the fork: https://github.com/peterflynn/JSLint/compare/pflynn/fix-for-newCEF.