Given a reference genome as a BSgenome object and some ranges on that reference, this function will return a vector of the same length as the granges object, with percent of Cs and Gs.
calcGCContent(query, ref)
A numeric vector of list of vectors with the GC percentage of the query regions.
if (FALSE) { # \dontrun{
bsg = loadBSgenome('hg19')
gcvec = calcGCContent(vistaEnhancers, bsg)
} # }