Implements multiple imputation for proportional hazards regression
with interval censored data or proportional sub-distribution hazards
regression for interval censored competing risks data. The main functions
allow to estimate survival function, cumulative incidence function, Cox
and Fine & Gray regression coefficients and associated variance-covariance
matrix. 'MIICD' functions call 'Surv', 'survfit' and 'coxph' from the
'survival' package, 'crprep' from the 'mstate' package, and 'mvrnorm' from
the 'MASS' package.