Changing launch4j path from non-relative to relative

because that allow it to run in other environments
Changing the Core.jar entry point

because that allow it to run
Removing unused projects from build script

because they aren't used
Removing dev/JDownloader.jar

because it doesn't have meaning when the build/newBuild/build.xml output update/dist/JDownloader.jar can be used instead of dev/JDownloader.jar
Adding Travis CI script

because it's useful to test a build