lock the emergency exit stairwell doors

during the last fire drill a problem was brought to my attention by Brad Westwood-- the doors in the emergency exit stairwells are periodically unlocked. This is problem for several reasons:
1. People are able to access areas they should not (i.e. special K) anytime the building is evacuated (fire drill, false alarm, flood problem, etc). Brad is especially concerned about this, for obvious reasons.
2. Patrons will begin to get the mistaken impression that it is possible to use the EE stairwells to transit floor to floor. On some doors this is unavoidable (the 3rd floor doors in the NW are left dogged down, the NW upper floors do not have locks) but on the ones that can lock, they should be.

In my personal opinion, this is not part of some malicious plot by some insider to make the library vulnerable, I think we're just not relocking the doors when we check chexits.

And so, brothers and sisters, now is the time to redouble your efforts. Ensure emergency exit stairwell doors are locked. If you're on rove and bored, check all the doors to make sure you can't get back in the library once inside. The only way out should be the emergency exit itself, thus preserving the original intent of the setup.

And thus it is.