Add step tree dispaly.

example/failing

@@ -0,0 +1,11 @@
+arbre
+1 mort
+
+mort
+2 feur
+
+feur
+1 arbre
+
+1 feur
+1 barbe

example/mc-induction-cell

@@ -0,0 +1,48 @@
+1 elite induction cell
+
+elite induction cell
+1 elite energy cube
+4 advanced induction cell
+4 energy tablet
+
+advanced induction cell
+1 advanced energy cube
+4 basic induction cell
+4 energy tablet
+
+basic induction cell
+1 basic energy cube
+4 lithium dust
+4 energy tablet
+
+elite energy cube
+1 advanced energy cube
+4 reinforced alloy
+2 gold ingot
+2 energy tablet
+
+advanced energy cube
+1 basic energy cube
+4 enriched alloy
+2 osmium ingot
+2 energy tablet
+
+basic energy cube
+1 steel casing
+4 redstrone dust
+2 iron ingot
+2 energy tablet
+
+steel casing
+1 osmium ingot
+4 steel ingot
+4 glass block
+
+energy tablet
+3 gold ingot
+2 enriched alloy
+4 redstrone dust
+
+reinforced alloy
+1 enriched alloy
+0.125 diamond