Allow different degrees of freedom for the same nesting level

[mattfidler]

library(lotri)
omega <- lotri(lotri(eta.Cl ~ 0.1) | id(nu=50), 
              lotri(eta.Ka ~ 0.1) | id(nu=100),
               lotri(eye.Cl ~ 0.05,
                     eye.Ka ~ 0.05) | eye(nu=200),
               lotri(iov.Cl ~ 0.01,
                     iov.Ka ~ 0.01) | occ(nu=200),
               lotri(inv.Cl ~ 0.02,
                     inv.Ka ~ 0.02) | inv(nu=10))
#> Error in .mergeProp(.prop, .fullCnd, .amplifyDefault(.tmp0, dimnames(.tmp[[.fullCnd]])[[1]])): conflicting 'nu' properties

^{Created on 2020-07-13 by the reprex package (v0.3.0)}