'jungleleaves simple' had completely different leaf colours to
'jungleleaves', now matched.
'leaves simple' had dark green instead of black colour for transparent
pixels (the 'leaves' texture uses black), normally these pixels would
not be rendered as opaque colours but bush nodes now use this texture
and will be rendering it as opaque. The dark green pixels resulted in
a texture lacking in contrast.
River water needs to be 'liquid_renewable = false' to avoid a mess caused by
spreading of sources, however picking it up with a bucket then creates
a hole in the river. Allow a 'force-renew' of the source node if it has a
source neighbour.
Pass nodename to tnt.burn function where possible to reduce
use of 'get_node'.
Change 'ipairs' to 'pairs'.
Use 'nodeupdate_single(pos)' instead of 'nodeupdate(pos)' to
avoid every node triggering recursion, the loop itself takes
the place of recursion and works upwards through horizontal
planes as required.
Credit to tenplus1 for the suggestion to generalise for mod use.
Mods can add mod nodes to 'group:spreading_dirt_type' enabling the
function to work with mod nodes.
Add some nodes to this group.
Removing 'dirt_with_grass' etc. from 'neighbors' stops the ABM action
running everywhere and constantly, on the dirt nodes immediately below
the surface nodes. Now the action only runs in the rare case of a dirt
node with neighbouring air, grass decorations or snow.
Remove check for air above to allow grass to spread under light-
transmitting nodes such as fences, walls, plants. This causes spread
under slabs, stairs and glass, when near air, but seems worth it.
Remove unnecessary check for nil node.
