updated openstc.task.recurrence to handle task-plannification when recurrence.plan_task is True; updated calculation of todo_tasks function-field; bugfixed store-related-function when deleting tasks
updated openstc.task.recurrence to handle task-plannification when recurrence.plan_task is True; updated calculation of todo_tasks function-field; bugfixed store-related-function when deleting tasks

OpenSTC-Eleger/stc-interventions