Use an overlay over default_dirt.png for soil
Add obsidianbrick

use Zeg9`s texture
Add white to the crack texture

This makes the crack stand out better on dark textures,
like obsidian and black wool.
Add 3D signs
Pinetree (by sfan5, from mg mapgen) lua generation and sapling ABM. Add checks for ignore to other trees
Screwdriver rewrite
Cleanup
* Remove unused variables
* Fix wearing out of screwdriver
* Move magic numbers into constants
* Scale down texture
Only allow rotating nodes that could be dug
Give 4 obsidianbrick for 4 obsidian
Remove useless, empty callbacks
Remove weird constants in default
Add tree growing functions to game_api.txt
Restructure default/nodes.lua
Fix typo