greater commit than expected. informations from tank now stored into database; introduced a new switch "--recreate-database"

reactivated fallback and callback from lqs, fixed multiple lineins on engine level, having the problem that fallback does not start

checking free diskspace. send warnings (email & logging) and stop recorder if a critical value is reached.

got too many data from pv. data is now filtered => easier debugging. now it is only possible to comment this to disable this function

enabled API call for liquidsoap state (enabled & connected streams, enabled & recording recorder, enabled lineins and enabled lineouts)

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