FPGA TrackSim: GenScan re-factoring

This is the next installment of the re-factoring of the GenScan code. Here the old BinningBase has been split into three classes: -- BinDescBase which describes the variables for the track parameters for the binning -- BinStep which describes each step of the binning (this generalized the old code where the steps were hardwires to "slice", "scan", and "row") -- BinTool which contains a list of BinStep to define the full binning

@brosser you might want to start looking at these