Investigate whether or not MOAIGrid can render its quads faster

[patrickmeehan]

...

In thinking about this, doesn't seem like we'd get much from it. Each quad is uniquely textured with different UV coords... so we'd lose whatever we save by having to add dummy vertices between quads. All the triangles get batched and drawn in one shot anyway, so it's not clear that this will be any faster. Also, grids don't seem to be a performance bottleneck at the moment.

This is going to require some tweaks to the deck system (or some tricks render state) but could be a big performance boost. Right now grid tiles are rendered using individual triangles. We should be able to speed things up by rendering grids as triangle strips.