docs: readme

Author: epoberezkin

README.md

@@ -1,5 +1,7 @@
 # json-source-map
-Parse/stringify JSON and provide source-map for JSON-pointers to all nodes
+Parse/stringify JSON and provide source-map for JSON-pointers to all nodes.
+
+NEW: BigInt support.
 
 [![Build Status](https://travis-ci.org/epoberezkin/json-source-map.svg?branch=master)](https://travis-ci.org/epoberezkin/json-source-map)
 [![npm version](https://badge.fury.io/js/json-source-map.svg)](https://www.npmjs.com/package/json-source-map)