====
TODO
====
- move options into description; or: options with hints, after that description
- rework output of --help by using another format


=================
POSSIBLE FEATURES
=================
- query "pairwise disjoint"
- option reversed output
- string comparison based on local preferences (LC_ALL??) instead of just default
- query power set
- give out cartesian product of input sets
- give out minimum or maximum of output set
- new line character not OS specific (std::ifstream::open(..., std::ios::binary))


==============
OPEN QUESTIONS
==============
- Set difference: Allow only two inputs?
- Should option --ignore-case affect the regular expressions used in --input-separator and --input-element?
- How to connect parameters to their corresponding options: --superset=filename, --superset filename; -p=filename, -p filename?
- What possible features should be discarded?
