TODO

Bugfixes:
  - terminate immediately on errors

Features:
  - add output alignment options: none, expanding, absolute
  - add more output format options (e.g., pretty with disabled stat conversions)
    and create short options for them

Optimizations:
  - OpenMP reduction for summaries (needs OpenMP 4.0, GCC 4.9)
  - minimize lnf_rec_read() calls for summaries

Tests:
  - add tests for reading multiple input files at once to test multithreading
  - add tests for reading single/multiple very large files to test buffer
    switching
  - add tests for reading nonexistent/invalid/empty files in all modes. There is
    a possibility of a deadlock.

Documentation:
  - create a ChangeLog

Build:

Coding style:
  - switch to 4 spaces indentation
  - join multiline string
  - check 80 characters per line

Others:
  - suppress printing command-line error messages on all nodes