* Fixed an age-old light calculation bug causing solid blocks to filter their own light, fixed#375, probably fixed#288
Light spread reduction should be done based on the _target's_ light filter level, not the source.
* Revert "Fix Glowing Obsidian lighting"
This hack is no longer necessary.
This reverts commit 35c33ba980.
* Fixed wrong light levels for torch and redstone torch
* Take adjacent light levels and opacity changes into account, block light will now spread when an obstruction is removed, close#455
* Added timings for Level->setBlock() and lighting updates
