Pass the original block in redstone propagation

notifyBlockOfStateChange and notifyNeighborsOfStateExcept expect the
block which caused the redstone update, rather than the neighbor block.

Fixes #393

src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java

@@ -141,7 +141,7 @@ public class TileTurtle extends TileComputerBase
             // Just turn off any redstone we had on
             for( EnumFacing dir : EnumFacing.VALUES )
             {
-                RedstoneUtil.propogateRedstoneOutput( getWorld(), getPos(), dir );
+                RedstoneUtil.propagateRedstoneOutput( getWorld(), getPos(), dir );
             }
         }
     }