Feature/eclipse

This adds the compileOnly and testCompileOnly to eclipse, but only if plugin eclipse is applied. If you use the SpringSource ToolSuite Gradle Integration, this is automatically done -- you don't have to apply it in your build script.

I would also suggest to change the idea configuration to use the same, because not every developer uses idea. 

I also removed the applyPluginIfAbsent-Method, because it is not necessary.