Rework of NDS2 interface (gwpy.io.nds)
This PR attempts to simplify the nds2 API by centralising more of the query methods in the gwpy.io.nds2
module, hopefully reducing the complexity of methods for the TimeSeries
and Channel{List}
.
additionally, the TimeSeries.fetch
method has been separated into two parts with a new gwpy.timeseries.io.nds2
module providing the low-level iterate wrapper.