Add 'absolute value' option to noise map functions
Extend persistence modulation to 3D noise
Extend 'eased' option to noise2d_perlin* functions
Some noise.cpp formatting fixups
See: https://github.com/minetest/minetest/issues/1525
Background
Wuzzy2: If you attempt to spawn a L-system tree with minetest.spawn_tree, you can make Minetest crash if it is attempted to pop an empty stack.
ShadowNinja: This shouldn't cause a segmentation fault, but it should throw a Lua error
Commit Description
This commit throws a Lua error instead of causing a segmentation fault. The server will still "crash" but will include a Lua backtrace.
L-Systems fix randomness
Unless a random seed is provided (via Lua treedef) seed the PRNG with a different seed for each tree
Resolves: https://github.com/minetest/minetest/issues/1469
Fix l-system crash when treedef random_level not set by Lua
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)
