Ask user whether he really wants to use non-grml folder
Adverb is actually adjective.
Silence errors the right way.

Catch exceptions per operation (for-loop) per value (iterator).
Implement folder cleanup support for TMPFILES. Closes #5.
Provide log message for umounted device in cleanup()
Create copies of set before iteration
Silent error for StandardError, not RuntimeError

RuntimeError was caught to catch set modification during iteration.
Now I want to catch all system-related exception.
More consequently use "Grml" instead of "grml"