B2OC: restore previous D0 mass range, cleanup and more files in hlt2_b2oc_example.py
- modified: Hlt/Hlt2Conf/options/examples/b_to_open_charm/hlt2_b2oc_example.py: cleanup and more files
- modified: Hlt/Hlt2Conf/python/Hlt2Conf/lines/b_to_open_charm/builders/d_builder.py for the D0 mass range