Fix error condition in eval,FilterRules


git-svn-id: https://hedgehog.fhcrc.org/bioconductor/trunk/madman/Rpacks/IRanges@75812 bc3139a8-67e5-0310-9ffc-ced21a209358
adding new IntervalTree code
Merge branch 'master' of https://github.com/hcorrada/IRanges