clean up for slim matchbox output
-------------- This line add the following will be ignored --------------

modified:
  madgraph/iolibs/export_cpp.py
  madgraph/iolibs/group_subprocs.py
  madgraph/iolibs/template_files/matchbox_class.inc
  madgraph/iolibs/template_files/matchbox_matrix.inc
unknown:
  MG5_debug
  additional_command
  input/mg5_configuration.txt
  madgraph/iolibs/template_files/matchbox_function_definitions.inc
  models/mssm/model.pkl
  models/sm/model.pkl