Windpower to the grass

After some hacking around with the NaiveVegetation java code I couldn't find a nice way to improve the look of the grass. Tried to set quads' rotation with no success, so now I won't force it anymore. Anyway while doing this I found a simple way to represent wind on the grass. Now it's moved around small distance with a moderate or high frequency, depending on the power of the wind. Although we don't have the climate's wind connected into 3D space's windpower, but it won't be a hard thing now to do this at least to the grass. Check out the SVN repository to look at the dynamically oscillating grass! :-D I hope it will look cool with a high windpower and the lightning strike effect which I plan to add later (at least a flashing is planned be added to the storm effects if not the view of a lightning).