Added Office Tower Floor 1 and Basement (2x2)

Floor 2 is pending Z-level code...
Connecting Basement for Office Tower
Added Office Tower Floor 1 and Basement (2x2)
Adding Zombies to Office Tower
Stopped Zombies from Spawing in Walls

There can be zombies stuck in the elevator but that is more of a "feature" rather than a bug.
Merge remote-tracking branch 'dda/pr/846' into dda-master