JUnit test added for preparing integration-test in nar-maven-plugin.
NarSystem.java should be kept. If the "packageName" is "native-lib-loader:<package>", we consider this using native-lib-loader.
Therefore, the "import org.scijava.nativelib.NativeLibraryUtil;" is inserted and "NativeLibraryUtil.loadVersionedNativeLibrary()" function is used instead of using "System.loadLibrary()".