added level 4 as potential start_level in run_prepro_levels (#1384)
added level 4 as potential start_level in run_prepro_levels (#1384)

* added level 4 as potential start_level in run_prepro_levels

* added file downloading/copying when starting level is >= 3
OGGM/oggm,bearecinos/oggm,OGGM/oggm,bearecinos/oggm,TimoRoth/oggm,TimoRoth/oggm,anoukvlug/oggm,anoukvlug/oggm