Remove delegateBy* functions

- reduceBy* functions have replaced the delegateBy* functions
- update BamFileViews man page
- remove "scanBam" and "countBam" methods for BamFileViews


git-svn-id: https://hedgehog.fhcrc.org/bioconductor/trunk/madman/Rpacks/GenomicFileViews@87239 bc3139a8-67e5-0310-9ffc-ced21a209358
Merge branch 'local-hedgehog'