New version
    
    - Update specs.rst to use present-tense and current API (agrover)
    - Add functions using BLOBs as LUKS passphrases (vpodzime)
    - Make sure the _error_quark() functions are in the library (vtrefny)
    - Return a special error when trying to wipe empty device (vtrefny)
    - Adapt tests to use LIO devices instead of loop devices (vpodzime)
    - Add functions for creating and deleting LIO devices (vpodzime)
    - MDRAID: Allow path as input for functions that work with sysfs (vtrefny)