Fixed stairs & chests rendering

-Fixed chests rendering in inventory (kinda).
-Fixed stairs rendering.
From now on, all blocks with multiple states MUST have item model.
Example stair provided (though with incorrect textures).
Relates to #9.

src/main/java/appeng/block/AEBaseStairBlock.java

@@ -33,7 +33,7 @@ import appeng.core.features.IAEFeature;
 import appeng.core.features.IFeatureHandler;
 
 
-public abstract class AEBaseStairBlock extends BlockStairs implements IAEFeature
+public abstract class AEBaseStairBlock extends BlockStairs implements IAEFeature, IHasSpecialItemModel
 {
 	private final IFeatureHandler features;
 

src/main/java/appeng/block/storage/BlockSkyChest.java

@@ -44,6 +44,7 @@ import net.minecraftforge.fml.relauncher.SideOnly;
 
 import appeng.api.util.AEPartLocation;
 import appeng.block.AEBaseTileBlock;
+import appeng.block.IHasSpecialItemModel;
 import appeng.client.render.tesr.SkyChestTESR;
 import appeng.core.features.AEFeature;
 import appeng.core.sync.GuiBridge;
@@ -52,7 +53,7 @@ import appeng.tile.storage.TileSkyChest;
 import appeng.util.Platform;
 
 
-public class BlockSkyChest extends AEBaseTileBlock implements ICustomCollision
+public class BlockSkyChest extends AEBaseTileBlock implements ICustomCollision, IHasSpecialItemModel
 {
 
 	public static enum SkyChestType

src/main/java/appeng/client/render/tesr/SkyChestTESR.java

@@ -49,7 +49,15 @@ public class SkyChestTESR extends TileEntitySpecialRenderer<TileSkyChest>
 		}
 		else
 		{
-			this.bindTexture( ( (BlockSkyChest) te.getBlockType() ).type == SkyChestType.STONE ? TEXTURE_STONE : TEXTURE_BLOCK );
+			// TODO 1.10.2-R - So this is weirdly half working. Either fix it or deal with it.
+			if( te != null )
+			{
+				this.bindTexture( ( (BlockSkyChest) te.getBlockType() ).type == SkyChestType.STONE ? TEXTURE_STONE : TEXTURE_BLOCK );
+			}
+			else
+			{
+				this.bindTexture( TEXTURE_BLOCK );
+			}
 		}
 
 		GlStateManager.pushMatrix();
@@ -64,9 +72,12 @@ public class SkyChestTESR extends TileEntitySpecialRenderer<TileSkyChest>
 		GlStateManager.scale( 1.0F, -1.0F, -1.0F );
 		GlStateManager.translate( 0.5F, 0.5F, 0.5F );
 
-		FacingToRotation.get( te.getForward(), te.getUp() ).glRotateCurrentMat();
+		if( te != null )
+		{
+			FacingToRotation.get( te.getForward(), te.getUp() ).glRotateCurrentMat();
+		}
 		GlStateManager.translate( -0.5F, -0.5F, -0.5F );
-		float f = te.getPrevLidAngle() + ( te.getLidAngle() - te.getPrevLidAngle() ) * partialTicks;
+		float f = te != null ? te.getPrevLidAngle() + ( te.getLidAngle() - te.getPrevLidAngle() ) * partialTicks : 0;
 
 		f = 1.0F - f;
 		f = 1.0F - f * f * f;

src/main/java/appeng/core/features/AEBlockFeatureHandler.java

@@ -36,6 +36,7 @@ import net.minecraftforge.fml.common.registry.GameRegistry;
 import net.minecraftforge.fml.relauncher.Side;
 
 import appeng.api.definitions.IBlockDefinition;
+import appeng.block.IHasSpecialItemModel;
 import appeng.client.render.model.AEIgnoringStateMapper;
 import appeng.core.AppEng;
 import appeng.core.CreativeTab;
@@ -101,7 +102,14 @@ public final class AEBlockFeatureHandler implements IFeatureHandler
 	@Override
 	public void registerModel()
 	{
-		Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "normal" ) );
+		if( !featured.getBlockState().getProperties().isEmpty() || featured instanceof IHasSpecialItemModel )
+		{
+			Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "inventory" ) );
+		}
+		else
+		{
+			Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "normal" ) );
+		}
 	}
 
 	@Override

src/main/java/appeng/core/features/AETileBlockFeatureHandler.java

@@ -41,6 +41,7 @@ import net.minecraftforge.fml.relauncher.Side;
 
 import appeng.api.definitions.ITileDefinition;
 import appeng.block.AEBaseTileBlock;
+import appeng.block.IHasSpecialItemModel;
 import appeng.client.render.model.AEIgnoringStateMapper;
 import appeng.client.render.model.CachingRotatingBakedModel;
 import appeng.core.AppEng;
@@ -122,7 +123,14 @@ public final class AETileBlockFeatureHandler implements IFeatureHandler
 	@Override
 	public void registerModel()
 	{
-		Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "normal" ) );
+		if( !featured.getBlockState().getProperties().isEmpty() || featured instanceof IHasSpecialItemModel )
+		{
+			Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "inventory" ) );
+		}
+		else
+		{
+			Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register( this.definition.maybeItem().get(), 0, new ModelResourceLocation( registryName, "normal" ) );
+		}
 	}
 
 	@Override