Correct origin association for record 'AE'.
Strip strings used for 'agency_id'.
Fix for magnitude attributes.

- 'agency_id' for main magnitudes defaults to 'USGS-NEIC';
- Additional magnitudes (field 'AE') are created only if > 0.0;
- 'agency_id' is correctly attributed for additional magnitudes.
Assign 'waveform_id' to 'amplitude' and 'station_magnitude'.
arrival.earth_model_id