Short term:
  - implement configuration file;
  - rework diff-ing of metadata;
Medium term (before beta release):
  - implement other commands (stat, check);
  - implement test suite;
  - reorganize the encoding of data payload;
  - finish user manual (quickstart maybe?);
Long term (post 1.0):
  - think about renaming and deletion;
  - analyze implementing non-sql repository;
  - think about delta storage;
  - add 'export' command which makes a tar of
    a given revision; then we can measure with
    bakonf
  - unify search options to different subcommands
