## User Story <!-- A clear and concise description of how the feature works and looks like from the user's perspective. Ex. I want to be able the stop the running pipeline by pressing a stop button. If the pipeline is stopped, I see a info-level message confirming it in the logger, if it fails the message should be displayed in red (error). Also, all the progress bars in the nodes must be set to 0. --> ## Example <!-- Any file/screenshot/photomontage/video/website is provided for a better understanding of the request --> ## Definition of Done <!-- A clear and concise description of what the feature requires. 1. Play button turns into stop button when pipeline is running 2. Stop button turns into play button when pipeline is finished 3. Stop button turns into play button when pipeline is successfully stopped 4. Logger displays messages everytime the play/stop button is pressed 5. Progress bars are set to 0 when stopping pipeline 6. Stop button has a Python interface -->
