Removed WithFilledDatabase and worked over some tests

After refactoring the tests I was able to remove ```WithFilledDatabase```. It is not perfect yet, but the build passing again. So I think, you could merge my changes to keep our repositories in sync.

I also added a configuration for Travis CI. So you can monitor the current build state directly from the project page. There is also an email notification. The configuration for the service hook is pretty straight forward. Just enable the service hook via the repository settings and follow the instructions on the Travis website. After that, you should change the link to the status image in ```README.md```.