add brick calculation code; doens't exactly agree with DJS IDL code yet
add brick calculation code; doens't exactly agree with DJS IDL code yet

timahutchinson/desispec,desihub/desispec,profxj/desispec,desihub/desispec,profxj/desispec,gdhungana/desispec,timahutchinson/desispec,gdhungana/desispec