Owl_countmin_table.Owlval init : int -> int -> t``init l w`` generates a table with length ``l`` and width ``w``, all counters initialized to 0.
val incr : int -> int -> t -> unit``incr i j t`` increments the counter at length index ``i`` and width index ``j`` in table ``t``.
val get : int -> int -> t -> int``get i j t`` gets the value of the counter at length index ``i`` and width index ``j`` in table ``t``.