add skip_before to default_options

binarycpython/utils/population_extensions/grid_options_defaults.py

@@ -168,6 +168,7 @@ class grid_options_defaults:
             "_total_probability_weighted_mass_run": 0,  # To count the total mass * probability for each system that thread/process has ran
             "modulo": 1,  # run modulo n of the grid.
             "start_at": 0,  # start at the first model
+            "skip_before" : 0, # skip models before this
             ## Grid type evolution
             "_grid_variables": {},  # grid variables
             "gridcode_filename": None,  # filename of gridcode