Editor questions belong in the world editor help zone on this site, not in the request section.
To rotate a placed building in the game I first place the building, change it's type to unit instead of structure, select the unit and right click on a point on the map to rotate it to the desired angle. Then I change it back to the structure type and it stays at that angle.
Under the view tab at the top of the screen you will see half way down it has 'grid'.... you can turn it off in there. Right down the bottom of the view tab you will also see things like 'lock to game view settings' which will make the map appear more like it does ingame.