[BioC] Erratum: intensities from a print-tip

[Laurent Gautier]

'just noticed that a missing ',' sneaked in the code
just suggested. One should read:

getRfprinttip <- function(x, tip) {
  z <- maPrintTip(x) 
  r <- maRf(x)[z == tip, ]
  return(r)
}


L.