Replace custom Timeseries class with Obspy Stream and Trace

src/python/geomag/io/Timeseries.py

src/python/geomag/io/TimeseriesException.py

src/python/geomag/io/TimeseriesFactory.py

src/python/geomag/io/Timeseries_test.py

src/python/geomag/io/iaga2002/IAGA2002Factory.py