S4 marker subclasses of MizerParams and MizerSim that enable S3 dispatch
for shelf-specific methods such as steady(), scaleModel(),
removeSpecies(), addSpecies(), and getBiomass().
Details
Objects of class mizerShelf are created by newDetritusCarrionParams().
Objects of class mizerShelfSim are returned automatically by project()
when called on a mizerShelf params object.