FileVersions - comment added
FileVersions - add test
Journal _add_file work with versioned files

+ tested
+ minor optimization for _delete_file
+ FileVersions::all
FileVersions - test improved and comment added about alternative formula
FileVersions - tests improvements
FIleVersions - delete_by_archive_id functionality
Journal file reading improvement

when reading journal add all archives to per-archive hash.
process deleted archives.
and only after then compose per-file hash.
+ fix tests