Simplify placement logic of various blocks

- For those where placement is stored in the metadata (computers),
   don't also set it in onBlockPlacedBy.
 - Remove .getDefaultState(int, EnumFacing) override, as this means we
   have more control over what is passed to us (namely, placer's
   direction too).

src/main/java/dan200/computercraft/shared/common/BlockGeneric.java

@@ -10,7 +10,6 @@ import net.minecraft.block.Block;
 import net.minecraft.block.ITileEntityProvider;
 import net.minecraft.block.material.Material;
 import net.minecraft.block.state.IBlockState;
-import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
 import net.minecraft.tileentity.TileEntity;
@@ -31,8 +30,6 @@ public abstract class BlockGeneric extends Block implements ITileEntityProvider
         this.hasTileEntity = true;
     }
 
-    protected abstract IBlockState getDefaultBlockState( int damage, EnumFacing placedSide );
-
     protected abstract TileGeneric createTile( IBlockState state );
 
     protected abstract TileGeneric createTile( int damage );
@@ -53,14 +50,6 @@ public abstract class BlockGeneric extends Block implements ITileEntityProvider
         }
     }
 
-    @Nonnull
-    @Override
-    @Deprecated
-    public final IBlockState getStateForPlacement( World world, BlockPos pos, EnumFacing side, float hitX, float hitY, float hitZ, int damage, EntityLivingBase placer )
-    {
-        return getDefaultBlockState( damage, side );
-    }
-
     @Override
     public boolean removedByPlayer( @Nonnull IBlockState state, World world, @Nonnull BlockPos pos, @Nonnull EntityPlayer player, boolean willHarvest )
     {