EcalCondDB.py again

with

CondTools/Ecal sa4

iovs are properly handled. I have added the function listiovs, example

./EcalCondDB.py --listiovs -t EcalIntercalibConstantsMC_EBg50_EEnoB

Now all functions not only need tag specification, but also since and till :

./EcalCondDB.py --compare=comp.png -t EcalIntercalibConstants_mc --since=1 --till=inf -t EcalIntercalibConstantsMC_EBg50_EEwithB --since=1 --till=inf

Note that "inf" is short for 4294967295

./EcalCondDB.py --histo=h.png -t EcalIntercalibConstantsMC_EBg50_EEnoB --since=1 --till=4294967295