Fix modstore/favourites hang by adding asynchronous lua job support
Fix old gcc build
Fix broken thread stop handling
Cavegen: Respect is_ground_content MapNode setting; fix some code formatting issues
Fixed potential NULL pointer and leak when setting node metadata
LuaVoxelManip: Add get_light_data() and set_light_data()
LuaVoxelManip: Add area parameters back to calc_lighting and set_lighting, made optional this time; also fixed a slight bug with night values being ignored
Change default value of is_ground_content to true

Most modders would otherwise forget to explicitly define this, and generated nodes aliased from mods would wall-off caves