Updated changelog

Author: Kevin Seim

changelog.txt

@@ -8,6 +8,9 @@ Changes in version 3.0.0 (TBD)
 * Removed Spring framework support
 * Fixed IOUtil.getResource() to use ClassLoader argument (gc0109)
 * Added support for validating marshalled fields (gc0096)
+* BeanWriter now implements AutoCloseable
+* BeanReader now implements Closeable
+* Added SegmentBuilder.at(int) method
 
 Changes in version 2.1.0 (2014-09-06)
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