Use same version of jackson

As discussed at https://groups.google.com/forum/#!topic/framework-benchmarks/WM9k_hwkhLQ I have upgraded Jackson dependency for all test apps that use it to its latest stable version - 2.3.0.

I had problems to start the test apps for `undertow/` and `servlet/`. All others have been tested locally and they run fine.

The `servlet` application doesn't start because it requires JNDI setup that I don't have locally.

The `undertow` application doesn't print any errors/exceptions but it doesn't bind on port 8080 for some reason. The problem is the same even without the change for this pull request.

This PR is built on top of https://github.com/TechEmpower/FrameworkBenchmarks/pull/639, that's why the diff shows a bit more. Once https://github.com/TechEmpower/FrameworkBenchmarks/pull/639 is merged this PR will show only https://github.com/martin-g/FrameworkBenchmarks/commit/015ccf3b4f96c6be94a7612e37023fd33efb2026 as a change.