Determines whether a something has been done before.
Returns TRUE if a local variable (NW_L_DOONCE999) is not set and sets that variable, and returns FALSE if that variable is set.
This function will return TRUE once only for that object that called (it sets the local variable on OBJECT_SELF).
This function will fail easily if used in a general. Recommendation: DO NOT USE.
#include " nw_i0_plot "
author: Tom Cassiotis