Added zlib sources for Qt5 compilation.
Fixed label text in luaworlddialog.ui.
BuildingEd: Added shutters tile to window objects.
BuildingEd: Added "dormer" roof objects.  Added half-tile edges and corners.

Slopes and corners could only be whole tiles high, now they can be created
in 1/2-tile increments.
Fixed new map objects preventing the StampBrush cursor being updated.
Submap tiles outside a cell or adjacent map's bounds are not displayed.

When a building is placed outside a cell map, its tiles are chopped off by
WorldEd when generating binary .lot files.  This change allows the user to
see where that will happen.
Optimize MapDocument's loading of adjacent maps.

1) Only call WorldEdMgr::cellForMap() one time.
2) Gather up all MapInfo's passed to mapLoaded() and handle them together
   after a delay.  This avoids excessive repainting of the scene.
3) Use a QMultiMap instead of a QList when seeing if a MapInfo is of interest.
Make restoring the previous session faster & cleaner.

When starting up and opening the previous session's documents, don't switch to
each document tab as it is opened.  Instead, just leave the first document tab
as the current one while opening other documents.  Also prevent CompositeLayerGroup
from drawing during startup.

I also moved WorldEdMgr init into main.cpp because MainWindow::openLastFiles()
might not get called.
Added zlib1.dll to make-dist.tcl.