Patent infections (detection) about openmalaria HOT 2 CLOSED

Info from Tom:

I think there is probably an outstanding item that we should be able to set 
different detection limits for PCR and for microscopy, but at the moment there 
is only a single detection limit in any one simulation.

Ideally one should be able to specify `detectionLimitPCR` which would default 
to `detectionLimit` if it is not set, so that if the simulation needs to output 
both prevalence by PCR and prevalence by microscopy (or RDT) then it could do 
so.  This will be relevant when we analyse implications of different diagnostic 
technologies.

I think it should be on your TODO list with a low priority