Fixed faulty generation of surrogate ids
Refactor code
Merge pull request #772 from jidel/issue#771-missing_dunning

Fixed faulty generation of surrogate ids
Only include unreturned materials in second dunning
Added help from patrick and corrected some typos
Merge pull request #774 from jidel/issue#768-second_dunning

Issue#768 second dunning
merge 065f468, optimise performance by only initialising states on
startup
optimise performance by only initialising states on startup
optimise performance by only initialising states on startup, general
performance, cleanup
Merge pull request #777 from davherrmann/issue#776

Issue#776: Optimise performance
Merge pull request #775 from henningmu/add_help

Added help from patrick and corrected some typos
Merge pull request #778 from HumBuch/develop

release version 1.1.16