Diff against 7.15 extract

1. During extraction if the control information (CRC-32) is present, as in the default setting, at the end of the extraction, the codes are checked to verify that the files have been correctly stored.

2. -checksum the extracted files will be re-read and the SHA1 code verified. It is a measure that lengthens the times but increases safety.

3. -kill extract to dummy, 0-length files. Simulate a full restore (useful for strange filenames) Basically you can simulate a restore (for example on RAMDISK) using exactly all the extract function, without writing data. It is therefore not a list(), but a real extract(). extract() try to intercept the 'disk is full' error.

4. Interoperability Sometimes it's impossible to restore a *nix archive on Windows, for various reason: path too long and too 'strange' filenames. That's really bad (cannot restore data), so there are some new switches to handle those cases
   -utf change everything non latin to latin
   -fix255 shrink to 255 max length, avoid different case collision (pippo.txt and PIPPO.txt are be silently overwritten by 7.15).
   -fixeml compress .eml filenames
   -flat emergency restore of everything into a single folder.
   If all else fails, however, you can extract the content to Windows however 'weird' it was initially.