Fixing version check (#18)

- [x] added use-case example project and fixed CMake exports
- [x] moved nlohmann_json header-only dependency into private
- [x] replaced boost.program_options with custom CLI parser
- [x] replaced boost.test with doctest
- [x] removed dependency on boost
- [x] added `-static` suffix to static library name to avoid issues on
Windows.
- [x] added compiler warnings and refactored SimpleTree and libz2s
private sections.

Merge pull request #13 from DEIS-Tools/inconsistent_lookup

Inconsistent lookup

Merge pull request #14 from DEIS-Tools/dep_fix

fixing deps

Merge pull request #12 from RasmusRendal/master

Add support for using system version of libraries

Merge pull request #9 from DEIS-Tools/missing_action_impl

added missing implementation

Merge pull request #8 from DEIS-Tools/prepare-1.0.5

Updated libptrie to version 1.1.1

Merge pull request #3 from petergjoel/stable_libs

updated to stable version

reduced CMAKE version dependency

Merge pull request #2 from petergjoel/user_boost

updating mostly build-system and printing

fixed issue with loading strategies w/o statevars