Added "closet" to RoomDefNameDialog's list of room names.
BuildingEd: allow "none" floor tiles.

Why? Cuz Mash wanted it.
Added EdgeTool and EdgeToolDialog.
Fixed bogus error message in TemplatesFile.
EdgeTool erases tiles in dash gaps.
Added CurbTool.
Added missing Edges.txt.
Late commit of tiled.pro (added CurbTool).
Added MapNoBlend, NoBlendTool, etc.

MapNoBlend contains a boolean table of all the tile locations in a single layer
where automatic blend tiles should not be drawn.

NoBlendTool is used to toggle blending on/off.

When NoBlendTool is current, any no-blend locations in the current layer are
displayed using noblend.png.
Added CurbToolDialog, default curb layer, and option to suppress blend tiles.
Improved the appearance of CurbTool and EdgeTool cursor items.
CurbTool only erases known blend tiles.
CurbToolDialog restores settings only once.
Added reading and writing of MapNoBlend.
Improvement to NoBlendTool.

Hide the cursor and prevent painting when the current layer is not a blend
layer.  I tried enabling/disabling the tool when the current layer isn't a
blend layer, but that was annoying due to another tool becoming selected.

Only erase known blend tiles.

Fixed incorrect QRect being used when setting bits.
TileLayersPanel displays BMP-generated tiles, not just map tiles.
TileLayersPanel gained a scale combobox.
TileLayersPanel is updated for all tools, hold Alt key to prevent this.

Previously, only StampBrush updated TileLayersPanel when Alt was held down.
Now, MainWindow updates TileLayersPanel when the mouse moves unless Alt is down.
Fixed TilesetDock combobox showing invalid scales.

Calling Zoomable::setZoomFactors() should update the combobox.
Improvments to CurbTool and EdgeTool.

Curb.mLayer and Edges.mLayer specify the name of a layer to switch to when
a curb/edge is selected in the tool's dialog.  This replaces the "Layer" field
in CurbToolDialog.

EdgeToolDialog gained an option to suppress blend tiles.

Curbs.txt and Edges.txt are read again if they are modified.  This happens when
switching to the tool.

CurbFile and EdgeFile check for valid block/value names.