Updates the Checkstyle core to version 6.16.1
Please note that this version requires Java 7 as the minimum runtime environment. This requires you to run Eclipse on a Java 7 (or newer) JVM in order to use this plugin version.
This restriction does not affect the ability to analyze Java 5 or lower level source code.
Please read the Checkstyle release notes for details on recent changes in Checkstyle.