Calculates risksets needed for using family multistate.
buildrisksets(entry, exit, trans, event, statusinfo)a vector with entry times.
a vector with exit times.
a vector with transition types.
a vector with noncensoring event indicators.
a logical indicating if information on the calculation process should be printed.
A list of length 2 with elements Ci and Ri, each
vectors of length n.
This function calculates riksets needed for family multistate.