Changelog for histogram-fill-

Changes in * Constructor of @HBuilderM@ exported. Changes in * @toHBuilderM@ added and internal definition of @HBuilder@ is changed. It required adding dependency on @monad-primitive@. * @joinHBuilder@ and @treeHBuilder@ are deprecated. Changes in * Function for searching for minimum/maximum added. * @NFData@ instance is fixed. Changes in * @mkStatefulBuilder@ is added and HBuilder constructor is exposed. * Indexing operators for immutable histograms are added. Changes in * fromMaybeBin added. Changes in * breduceX and breduceY are added. Changes in * mkFoldBuilder is added to @Data.Histogram.Fill@ * fill functions in @Data.Histogram.ST@ are replaced with generic variant. * Indexing for immutable histograms is added and special constructor for first and last bin are added to @HistIndex@ data type. * Functions to calculate sum, minimum and maximum of immutable histogram are added. Changes in * MaybeBin added. * Helper function for defining Read instances for bins are exposed. * mapData function is added. * Slicing histogram do not results in crash if indices are out of bounds. * Eq instances for BinF and BinD are added. * NFData instance for Bin2D is fixed. Changes in * Helper function and type synonym for Bin2D Changes in * Fixed compilation with GHC 7.4