(empfile, chr_camap): Merge chr_camap[] into empfile[]. No existing

user sees the new elements of empfile[].
(EF_SECTOR_CHR, EF_SHIP_CHR, EF_PLANE_CHR, EF_LAND_CHR, EF_NUKE_CHR)
(EF_TREATY_CHR, EF_ITEM, EF_INFRASTRUCTURE, EF_PRODUCT): New.  Not yet
used.
(my_ef_byname): Replacement for ef_byname() that sees the new
elements.
(xdchr): Work with empfile[] instead of chr_camap[].
(xdump): Use my_ef_byname() instead of ef_byname() and
chridx_by_name().
(camap, chr_camap, chridx_by_name): Remove.

src/lib/common/file.c

@@ -362,8 +362,8 @@ ef_mtime(int type)
 }
 
 /*
- * Return the filedescriptor used for the file containing objects of type
- * 'type'.
+ * Search empfile[0..EF_MAX-1] for element named NAME.
+ * Return its index in empfile[] if found, else -1.
  */
 int
 ef_byname(char *name)