Toggle WQ Caching

Added an option to Makeflow which disables WQ caching.

Addresses issue #163.

There did not appear to be a clean way to propagate the status of cache disable to `batch_job_work_queue`. I prepended file names with an asterisk if caching is disabled. This syntax addition does not conflict with the previous mode of operation and does not conflict with file names since an asterisk is invalid in file names.