Use the same version of Jackson for JSON tests

As discussed at https://groups.google.com/forum/#!topic/framework-benchmarks/WM9k_hwkhLQ
PR #640 Remove newly added jetty-maven-plugin.

Its purpose was to run the app as a smoke test to verify it is not broken.
But it doesn't work atm.
Merge branch 'use-same-version-of-jackson' of https://github.com/martin-g/FrameworkBenchmarks into PR640

Conflicts:
	netty/README.md
	netty/pom.xml