Composite doesn't work when a cluster is missing

@vtorralba detected that Composite fails in this case:

data <- 1 : (4*5*6)
dim(data) <- c(lon = 4, lat = 5, case = 6)
occ <- c(1,1,2,2,4,4) 
res <- Composite(data, occ)

But it is a small bug already fixed in this branch develop-Composite.

Could you consider to included for the next s2dverification release?

We need it for CSTools next release, we can discuss in the coming weeks.

Cheers,

Núria