Optimization for the Caves

jcrpg received simple but huge optimization with lessening the view distance of outside objects when inside the cave, and the opposite also, when moving outside in the nature, the models inside the cave are rendered with a much lower view distance (all this is done in J3DCore.renderToViewport, each cube is checked for internalLight boolean property against the current player positions' inside or outside flag) . This boosts the performance much. It will be usable everywhere, where internal parts are covered with external parts, so it doesn't matter if they are not rendered. So exactly the Caves are most excellent for such optimizations, as the mountain covers it totally. Later internal parts of big buildings can be covered by outside walls, and using this technique FPS eater internals will be cut out from scene.

Meanwhile the cave code received much perfection and bug fixing, it is nearing completion in its first form. I've found a culling problem when externalRootNode's children are in very low number (when player is inside the cave), the whole internal scene was culled for no apparent reason. May be a JME bug, or what the heck! Anyway the solution is that when moving to internal parts from outside or back the order of internal root node and external root node are exchanged in its parent's child list (parent is the so called groundRootNode), and thus the problem goes away...maybe this is indicating a JMonkeyEngine bug or something I don't know about culling and node order?

I will think about some other geography improvements, maybe clean up things, adding comments to codes before moving on to wildlife. Before that you can expect a new prealpha release.