I use combination of Sptites and Tiled Background to lay down tileset - create level, and this problem ocures
<img src="http://dl.dropbox.com/u/37009800/problem%20example.png" border="0" />
<img src="http://dl.dropbox.com/u/37009800/problem%20example%203x%20zoom.png" border="0" />
everything is snaped to grid. There is no space between sprites/tiles, but when Constuct renders them small gap appears.
Beside of that I have one suggestion for some kind of "Tileset Background" object, something like combination of Tiled Background object and the way Panel object from CC works. First you import basic tileset, define tile size, and istead of stretching cener tile it just copy it... Here is basic idea:
<img src="http://dl.dropbox.com/u/37009800/TilesetBackground.jpg" border="0" />