zone id patch (seq5)

I noticed showeq wasn't picking up the maps correctly when zoning into some instance (missions). I think this should fix it, but I haven't tried it on all missions yet. Feedback welcome.

This was made against seq5's source tree. Should be easy to incorporate into seq6.

Thanks Newby! I've commited this to the SEQ5 trunk and the pre_6_0_beta branch.

Thanks Newby