Update readme for 20151123 release

[stleary]

Proposing a new release on 23 Nov 2015. No input has been received on generics support after 3 weeks, so proceeding with GitHub and Maven releases. Please comment if you see anything that was missed or have any new concerns about the release. For more information on how releases are made on this project, see https://github.com/douglascrockford/JSON-java/wiki/How-to-make-a-new-JSON-java-release

Label: 20151123
Title: JSONObject and JSONArray initialization with generics
Text: Provide support for generic maps and lists. A use case was identified where the JSONObject and JSONArray constructors could not be used to initialize Map<String, String>
and Collection<String> objects. In this release, Map<?,?> and Collection<?> initialization is
supported.

Includes the following commits:

Pull request	Description
#168	Update Readme for Maven release
#160	Fixe possible NullPointerException
#159	Properly override Exception class
#153	JSONObject and JSONArray initialization