removed unused util test file
added TODO
renamed action tests with prefix action_
properly detect failure in create_backup_directory

previously it would error if it succeeded. woops.
fixed a bunch of bugs in backup system

was not properly checking for errors when doing copies or symlinks (was
detecting errors when things should have been successful). stupid
forgetting !
added tests for backups.

fixed a bug in cleanup_old_backups. now actually keeps the number
specified.