Do not count fixed tim bins in time delay estimation

Some spectrogram bins have tiles so large in time that they contribute in a fixed way to time delay estimation. They do not add any information but a systematic bias. It has been observed that time delays are pushed toward the center of the slice because of this. They should not be included in the time delay estimation.

Add a if condition in OxEvent::ComputeEvent (OxEvent.cc L548) if (omicron_tile_duration >= OxOmicron::GetLightTravelTime() + delta_cal){ weight_dt =0.0; } else weight_dt = 4.0 * xi_max / omicron_tile_duration / omicron_tile_duration;

this has been done in this branch