Fix MaterialData directions being incorrect. Fixes BUKKIT-3160

Prior to 49690f9, BlockFaces were mostly correct in their respective
MaterialData classes. However, a lot of things were not updated since
implementation and broke without being addressed.

This fixes any discrepancies with Block data.

By: feildmaster <admin@feildmaster.com>

paper-api/src/main/java/org/bukkit/material/Stairs.java

@@ -60,22 +60,22 @@ public class Stairs extends MaterialData implements Directional {
         byte data;
 
         switch (face) {
-        case WEST:
+        case NORTH:
+            data = 0x3;
+            break;
+
+        case SOUTH:
+            data = 0x2;
+            break;
+
+        case EAST:
         default:
             data = 0x0;
             break;
 
-        case EAST:
+        case WEST:
             data = 0x1;
             break;
-
-        case NORTH:
-            data = 0x2;
-            break;
-
-        case SOUTH:
-            data = 0x3;
-            break;
         }
 
         setData((byte) ((getData() & 0xC) | data));