Add support for blocking file removal operations if ALL files from a set would be removed

[atc0005]

This application groups detected duplicate files into "sets". Each set contains all files that are duplicates of each other, including what could be considered the "original" file that is duplicated by others in the set.

The current implementation for file removal support (see #4) will honor a user-supplied "flag" in in the input CSV file to indicate that the file should be removed, even if the result is removing ALL files in a set. This issue is to extend the file removal support to accept a CLI-flag option to help prevent removal of all files in a set. Instead, when the application can determine that all files are marked for removal that set would be skipped (if config.IgnoreErrors is set perhaps?) or cause the application to immediately fail.

refs #4