Added two passive tracer fields which convect with the flow: One to estimate magnetic field polarity, initialised with Br at 30 rs. The other to trace CME position.
Updated plotting, animating and saving routines to visualise and store the new tracer fields
Added HUXtinput.py which contains new routines to download and process MAS output from MHDweb, replacing the stored MAS output as part of the distribution (now removed). Also moved the trace-inwards functions from HUXt to here. Thus processing of HUXt inputs and the HUXt model are now cleanly separated.
Added latitude as an input property to HUXt, in preparation for meridional cuts
Updated the jupyter notebook to provide examples of the new functionality.
Main changes: