added some code from my private repo: https://github.com/t-weber/qm/tree/a42a0407d7c73cf5a622f5f795553529d394b46c

added some gui code from my private "qm" project: https://github.com/t-weber/qm/tree/4b1d5ed42c0c510343587cf5da701b687caefe68

giving more feedback on path mesh calculation and preventing the user from starting the calculation multiple times

added resource class from https://github.com/t-weber/qm/commit/5491146c6dece143485312547c42bcd41e607e51