Added warning about serialized object and removed beta.

Right now I don't think we want to guarantee compatibility of
serialized object between versions (although they will likely
work fine). We can revisit this as we clarify our versioning.

Author: oschwald

README.md

@@ -2,14 +2,6 @@
 
 [![Build Status](https://travis-ci.org/maxmind/GeoIP2-java.png?branch=master)](https://travis-ci.org/maxmind/GeoIP2-java)
 
-## Beta Note ##
-
-This is a beta release. The API may change before the first production
-release, which will be numbered 2.0.0.
-
-You may find information on the GeoIP2 beta release process on [our
-website](http://www.maxmind.com/en/geoip2_beta).
-
 ## Description ##
 
 This distribution provides an API for the GeoIP2 [web services]
@@ -230,6 +222,8 @@ whenever possible.
 
 The GeoIP2 Java API uses [Semantic Versioning](http://semver.org/).
 
+Note: Serialized objects may not necessarily work between versions.
+
 ## Copyright and License ##
 
 This software is Copyright (c) 2013 by MaxMind, Inc.