New option: jarName and assemblyOption in packageDependency and packageScala

I think sbt-assembly's packageDependency and packageScala features are really great idea, really help a lot!

But what seems missing is that the jar name of packageDependency(packageScala) should be different with normally assembly. Or the packageDependency will lose its original use.

Also, packageDependency should provide the option in which user can choose whether to package scala library in, not forcing packageDependency user to end up with 3 packages(dependencies without scala, scala-library, bin)