Indicator function on a genome
module Selection: sigtype 'a t 
val intersects : 'a Biocaml_genomeMap.location -> 'a t -> boolintersects loc sel returns true if loc has a non-empty
        intersection with sel, and false otherwise.val intersection_size : 'a Biocaml_genomeMap.location -> 'a t -> intval to_stream : 'a t -> 'a Biocaml_genomeMap.location Stream.tval of_stream : 'a Biocaml_genomeMap.location Stream.t -> 'a tof_stream e computes a selection as the union of the locations contained in eend