L&S - Tree Generator

[Cervator]

Custom tree generator for new poker trees described in #541

Closest example class to clone might be org.terasology.world.generator.tree.TreeGeneratorLSystem

Functionality could be as simple as picking between a couple different block variants in the same simple shape. Alternatively we could use some sort of tree blueprint / grammar (to help support other L&S tree types later) but that might be too fancy.

[Cervator]

Moved out to the "extras" milestone after @skaldarnar tried the poker chip in-game and had it not turn out too pretty. Not high priority anyway, we got several other nice art assets making it in :-)

[rzats]

This issue was moved to Terasology/LightAndShadow#10