refactor example test runner to separate out doc parsing

I've split out the document parsing from running the example tests. I put `doc-parser.js` in `scripts`, is that a good place for it?

Now from anywhere you can do

`var ramdaDocs = require('path/to/doc-parser');`

and you get an array back of objects representing the docs for a given function. Objects are of the form

    {
        name: 'countBy',
        func: '',
        memberOf: 'R',
        category: [ 'relation' ],
        sig: '(a -> String) -> [a] -> {*}',
        param: [ [ 'Function' ], [ 'Array' ] ],
        return: [ 'Object' ],
        example: '\n     var numbers = [1.0, 1.1, 1.2, 2.0, 3.0, 2.2];\n     var letters = R.split(\'\', \'abcABCaaaBBc\');\n     R.countBy(Math.floor)(numbers);    //=> {\'1\': 3, \'2\': 2, \'3\': 1}\n     R.countBy(R.toLowerCase)(letters);   //=> {\'a\': 5, \'b\': 4, \'c\': 3}',
        description: '<p>Counts the elements of a list according to how many match each value<br />of a key generated by the supplied function. Returns an object<br />mapping the keys produced by <code>fn</code> to the number of occurrences in<br />the list. Note that all keys are coerced to strings because of how<br />JavaScript objects work.</p>',
        isPrivate: false,
        isConstructor: false,
        isEvent: false,
        ignore: false,
        line: 6092,
        codeStart: 6113
    }

This is slight re-organization of what you get back from `dox`. Might be more useful to index by function name? Anyway more stuff could be done here, but hopefully this is a decent start and something useful.