Upgrade JUnit to 4.11

Also, two questions: 
1. What do you think about migration of existing tests to JUnit 4 syntax (using IntelliJ Idea automated tools)?
2. What do you think about transforming existing set of micro-benchmarks to JMH (http://openjdk.java.net/projects/code-tools/jmh) benchmarks? Here is an example: https://github.com/kshchepanovskyi/protostuff-benchmark