Allow --path argument to point at artifact in addition to directory

[nebhale]

Currently, the --path argument only allows arguments that are directories. In the Java world, it's very common to have a single artifact (e.g. myapp.jar) and this restriction on a directory only is too restrictive.

The --path argument should allow individual files and either put that file as a single item within the application directory or expand the file into the application directory if it is an archive.

[ameyer-pivotal]

Duplicate of #106. We'll continue conversation there.