several things: critical socket threading bug from comba resolved. adapted interfaces to pv / tank / database

fixed the commit bug. one does not have to add a already existing object in the database to the session.

started to implement trackservice. removed unused (comba)methods from scheduler.py&calender.py. minor beautyness improvements

implemented manual inserting of a ScheduleEntry. Manual radio control is not far away. Found a - at least for me - hard to track bug coming from sqlalchemy session. not fixed

code quality enhanced, timer management improved, started to implement methods for manual playlist editing