Refactor "test" functionality with flags to show either parseable or unparseable files

[jrsmith3]

The refmanage "test" functionality should have flags to show either a list of unparseable files or a list of parseable files. These flags should be mutually exclusive. For parseable files, the flag should be "-p" or "--parseable". For unparseable files the flag should be "-u" or "--unparseable". If neither flag is used, the default behavior should be to display a list of unparseable files.

This issue is split from issue #32.