Added verbose switch
Added file-hash Dictionary and Linq selection of duplicate hashes
Added menu for user to select which file to keep
Added file deletion for duplicate lists
Cleanup and user feedback misc.
User can now specify to automatically keep oldest or newest files
Updated readme and normalized variables
Changed variable names and tweaked output
Removed '-ok' safety argument
Implemented searching for file sizes before checking real content

Duplicate files share the same size, so it is a bit more memory-efficient
to check for the file sizes first and only read contents of those files
which share the same size.

This way, the software won't overflow in memory due to reading files which
are only present once.
Added option for dry-running
Modified list possible duplicates: now ordered by file size, descending
Hackfixed duplicate key ArgumentException on ordering files by their atime
Merge pull request #2 from whisperity/master

Increase userland communication and improve internal logic