[ft] Bottom row of pixels getting clipped

[Joe Krahn]

When displaying the MS-Windows symbol.ttf font, the last row is getting 
clipped for most font sizes smaller than 32 pixels. This can be seen 
with ftsrting, which only shows the "missing char" box. That makes it 
easy to see the last row of pixels getting clipped.

It seems like some sort of rounding-down issue, and varies with transforms.

Joe Krahn