Update constants/formatting in "space_merc.h"
Update constants/formatting in "space_merc.h"

Updated some of the header file's formatting, added an array of location
string constants, and restored use of "enum" because I realized it
doesn't impact app size (what had previously been increasing app size
was the way I was using my own "typedef" integer types associated with
those enumerations).

theDrake/spacemerc,theDrake/spacemerc