Remove -c option

[defuse]

The -c option should be the default. Not using it is a useless performance optimization. If the program says "99.9% of the original is in the backup", then that 0.01% should NOT be one directory containing a billion files. The % should always be relative to everything in the original, no matter how much longer that takes.

[defuse]

Maybe by doing this the logic can be simplified, too. Instead of "counting", just iterate through everything in the original directory, and compare each object found. Then there's no special logic needed, just "yes this object matches" or "no this object doesn't match".

[defuse]

The option has been removed in the add-integration-tests branch. It will get merged in with the integration tests eventually, then this ticket can be closed.