Reogranized the script structure completely into 3 main functions: one to parse the root file, one to filter out the dictionary of xAOD objects found, and one to dump it into an output file in a very nice manner. Takes in an input file appropriately now as the first positional argument. Contains features that allow for different output formats (json, pickle, pretty). The filtering is almost complete as it is done on the xAOD Object level and the xAOD Type level. Updated readme with the output of `dumpSG.py --help` as that help is self-documenting and very decent.