Compute gene-sets overlap
 Calculates the overlap among every pair of gene-sets given as input.
 \S4method{computeGeneSetsOverlap}{list,character}(gSets, uniqGenes,,
 \S4method{computeGeneSetsOverlap}{list,ExpressionSet}(gSets, uniqGenes,,
 \S4method{computeGeneSetsOverlap}{GeneSetCollection,character}(gSets, uniqGenes,,
 \S4method{computeGeneSetsOverlap}{GeneSetCollection,ExpressionSet}(gSets, uniqGenes,,
   \item{gSets}{Gene sets given either as a \code{list} or a \code{GeneSetCollection} object.}
   \item{uniqGenes}{Vector of unique genes to be considered when calculating the overlaps.}
   \item{}{Minimum size.}
   \item{}{Maximum size.}
 This function calculates the overlap between every pair of gene sets
 of the input argument \code{gSets}. Before this calculation takes place,
 the gene sets in \code{gSets} are firstly filtered to discard genes that do not
 match to the identifiers in \code{uniqGenes}. Secondly, they are further
 filtered to meet the minimum and/or maximum size specified with the arguments
 \code{} and \code{}. The overlap between two gene sets is calculated
 as the number of common genes between the two gene sets divided by the smallest
 size of the two gene sets.
 A gene-set by gene-set matrix of the overlap among every pair of gene sets.
 \enc{H´┐Żnzelmann}{Hanzelmann}, S., Castelo, R. and Guinney, J.
 GSVA: Gene set variation analysis for microarray and RNA-Seq data.
 \emph{BMC Bioinformatics}, 14:7, 2013.
 \author{J. Guinney}
 geneSets <- list(set1=as.character(1:4), set2=as.character(4:10))
 computeGeneSetsOverlap(geneSets, unique(unlist(geneSets)))
 \keyword{Gene set}