add POMs so we can build with maven and use IDEs other than Eclipse

[aliedperezmartinez]

• Adapted the POMs to the existing structure.
• Isolate (as far as possible) tests from production code.

Additionally this will enable to add tests with more ease.

[aliedperezmartinez]

In addition to simplify headless build and isolate tests from production, maven allows to publish the artifacts and be used by external projects.

[DennisSoemers]

Hey, thanks for your pull request!

While I personally do like Maven, unfortunately we won't be merging this in. Most of our team members prefer to work directly in Eclipse without Maven, and it might for example also be easier for many of our students here who work with the project to not have to learn to work with Maven.