- 10 Dec 2013 M.Fuerstenau version 0.8.15
  - datastore_volumes_info()
    - Changed "For all volumes" to "For all selected volumes". This should fit all. The subroutine datastore_volumes_info
      is called from several subroutines and to make a difference here for a single volume or more volumes will cause
      a lot of unnecessary work just for cosmetics.
    - Fixed typo in error message.
    - Modified error messages
  - check_vmware_esx.pl
    - Removed plausibility check whether critical must be greater than warning. In case of freespace for example it must
      be the other way round. The plausibility check was nice but too complicated for all the different conditions.
    - check_against_threshold() - Cleaned up and partially rewritten.