Replace process_ids.R and process_shipdata.R with process_ships.R
New script:
/home/users/ekent01/nocgit/icoads-r-hostace/rscripts/process_ships.R
combines incorporation of date changes (was process_shipdata.R) with ID updates (was process_ids.R)
Because it needs data from +/- 1 month in some periods there is a check that the needed files exist and pauses until they are.