akt store: store files, directories or read standard input in the keystore

Usage: akt store <keystore>.akt <files|directories>
       akt store <keystore>.akt -- <name>

  This command can store files or directories recursively in the
  keystore.  It is possible to store several files and directories
  at the same time.

  When the -- option is passed, the command accepts only one
  argument.  It reads the standard input and stores it under the
  specified name.  It can be used as a target for a pipe command.
