add formatJSON and validateJSON examples

Author: brettlangdon

README.md

@@ -97,6 +97,10 @@ API
 jsfmt.format(<javascript_string>, <config_object>) // Returns formatted JavaScript
 ```
 
+```javascript
+jsfmt.formatJSON(<JSON_string>, <config_object>) // Returns formatted JSON
+```
+
 ```javascript
 var config = jsfmt.getConfig(); // Loads the jsfmt config from the appropriate rc file or default config object
 ```
@@ -155,6 +159,10 @@ jsfmt.search(js, "R.Component.create(a, { dependencies: z })").forEach(function(
 jsfmt.validate(<javascript_string>) // Returns errors found while parsing JavaScript
 ```
 
+```javascript
+jsfmt.validateJSON(<JSON_string>) // Returns errors found while parsing JSON
+```
+
 #### Example
 
 ```javascript