merge from bioc devel

git-svn-id: https://hedgehog.fhcrc.org/bioconductor/branches/RELEASE_2_14/madman/Rpacks/openCyto@91291 bc3139a8-67e5-0310-9ffc-ced21a209358
remove flowDensity
take care of hidden nodes during the recompute
merge from devel
Merge commit '667b2b08eaa8dd0503dfa8afa309f8a6cc538bfc'