Output strain data of the pipeline is needed to be trimmed

Around 0.5-1 second of initial strain data in output frames are always zero disregarding the start-time we give in command line. This will create either bad calibrated strain or overlapping frames. In order to resolve this issue, certain amount of data at the starting of the pipeline needs to be dumped at the frame writing level so that it does not appear in the output frames. This application might be similar to "wings" in gstlalcalibration pipeline. Also, this is more important in offline run.