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

(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.