Remove m_ext_ptr in GUIFormSpecMenu, replaced by refcount mechanism
Add NodeResolver and clean up node name -> content ID resolution system
Add support for eased 3d noise
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/biome.cpp
	src/guiFormSpecMenu.cpp
	src/noise.cpp
	src/noise.h
	src/script/lua_api/l_mapgen.cpp