getME() speedup: compute mmlist(), p_i and l_i only when needed
refit() : if(GLMM): build large list at once
add new predict(*, <new>) issues (with a FIXME, as they are *open* !)
white space (e.g., most of the time after ",")
cosmetic; fitted models: as fm0, fm1 are "global" models; use m<n> here