Change TileSpec::frames to be std::vector not std::map

Signed-off-by: Craig Robbins <kde.psych@gmail.com>
Re-add hacky fix for underwater grass, to fix mgv7 user's biomes
lua_api.txt: improve noise documentation. Remove previous eased 3D noise format example
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/mapgen_v5.cpp
	src/mapgen_v7.cpp
update games/default
fix warning