;EP - many
; given N, return category for the duplicate resolution process
; Can call with either N = integer IEN into 9002313.57
; or N = decimal IEN into 9002313.59
; $G(WANTREV) = true if you care about reversals
; (that's the default if N is an IEN59)
; $G(WANTREV) = false if you want to ignore reversals
; (that's the default if IEN57)
; because billing is handled differently.