risk/writers:
risk/writers:

Added LossMapGeoJSONWriter, which is basically the GeoJSON equivalent
of the LossMapXMLWriter.

I also abstracted a base LossMapWriter class to share code common to
all such writers.

raoanirudh/oq-risklib,vup1120/oq-risklib,gem/oq-engine,gem/oq-engine,raoanirudh/oq-risklib,g-weatherill/oq-risklib,g-weatherill/oq-risklib,vup1120/oq-risklib,g-weatherill/oq-risklib,gem/oq-engine,gem/oq-engine,gem/oq-engine