Clearing away JSHint warnings

I ran the helpful [JSHint](http://jshint.com) tool over complexityReport to look for potential sources of bugs. JSHint shows 48 trouble spots, but these all turned out to be clashes between JSHint and `"use strict";`.

    $ jshint .
    src\cli.js: line 5, col 1, Use the function form of "use strict".

    src\complexityReport.js: line 7, col 1, Use the function form of "use strict".

    src\formats\json.js: line 3, col 1, Use the function form of "use strict".

    ...

    src\syntax\WithStatement.js: line 3, col 1, Use the function form of "use strict".

    48 errors

I was able to clear all of these warnings away by adding `"node": true` to `.jshintrc`. Now complexityReport passes JSHint 100%!