bugfix: modify JarRunnerTest to remove dependency on system-specific newline code
use System.lineSeparator() rather than removing system-dependent line break code as disucussed in https://github.com/crawljax/crawljax/pull/268
Merge pull request #268 from daisy1754/fixes/267jar-runner-test-newline-code

Fix for issue 267: JarRunnerTest#assertHelpWasPrinted fails on Windows