Gather GATified MJD data into arrays of hits, with various cuts applied.
Save the gathered data in HDF5 files.

This code requires PyROOT, NumPy, and h5py.
Additionally, the env variables $MJDDATADIR, $CHANNELDATADIR, and $BDSOUTPUTDIR should be set.

The code can be run to:
-gather hits from all skim files of an open or blinded data set, e.g.
	BuildDataSpectra.py DS0 open
-gather hits from a specific skim file of an open of blind data set, e.g.
	BuildDataSpectra.py DS0 open --file_index 30
-stitch together hits previously gathered from specific skim files, e.g.
	BuildDataSpectra.py DS0 open --stitch

Usage:
	BuildDataSpectra.py [-h] [--stitch] [--file_index FILE_INDEX] data_set data_type