Impostor trees are incorrectly rendered

[Erik Ogenvik]

With the new glsl shaders, the imposter trees are incorrectly rendered. They both have fog applied and seem to be using too much alpha on the foliage.
I think that I did some fiddling with the Cg shaders to make the imposter trees be correctly rendered when they are rendered as imposters. It all happens in src/components/ogre/environment/pagedgeometry/source/ImpostorPage.cpp
The fog should be disabled, so the shaders need to take that into account.

[Erik Ogenvik (erik-ogenvik)]

It might be that the fog issue is also what's causing the incorrect rendering in the model editor (since the fog is disabled there too).

[Alexey Torkhov (atorkhov)]

Alpha on foliage should be fixed now.