Config settings:
profiling = true/false (gather statistics)
detailed_profiling = true/false (break mod times to callbacks)
Chat commands:
save_mod_profile saves current statistics in debug.txt and shows on console (on default loglevel)
On the lua side, notably minetest.env:<function>(<args>) should now
be replaced by minetest.<function>(<args>).
The old way is and will stay supported for a long time.
Also:
Update and clean up lua_api.txt (by celeron55)
Move EnvRef to lua and remove add_rat and add_firefly (by kahrl)
Add separate src/util/CMakeLists.txt, other minor fixes (by kahrl)