Nested params and json/yaml files

[lukfor]

Fixes #15

[aaron-fishman-achillestx]

This feature is very cool! Particularly how you can mix/match loading of json and defining locally.

My main comment is a suggestion to use an iterative rather than recursive schemes (I was always taught to use iterative over the latter when possible!).

[aaron-fishman-achillestx]

This could also be written iteratively:

	protected void evaluateNestedClosures(Map<String, Object> map) {

        Queue< Map<String, Object> > queue = new LinkedList< Map<String, Object> >();
        queue.add(map);

        while (queue.size() > 0) {
            Map<String, Object> item = queue.remove();

            for (String key : item.keySet()) {
                Object value = item.get(key);

                if (!(value instanceof Closure)) continue; 

                Map<String, Object> nestedMap = createNestedMap();
                Closure closure = (Closure) value;
                closure.setDelegate(nestedMap);
                closure.setResolveStrategy(Closure.DELEGATE_FIRST);
                closure.call();
                item.put(key, nestedMap);
                
                queue.add(nestedMap); // Instead of recursion
    
            }

        }
	}

[lukfor]

Great idea, thanks Aaron! 👍