Fix chunk index extracting negative y values

Make parts lose their tile reference on being removed, fixes crash with tick scheduler

codechicken/multipart/IRedstonePart.scala

@@ -103,7 +103,13 @@ object RedstoneInteractions
         if(p.isInstanceOf[IRedstonePart] && p.asInstanceOf[IRedstonePart].canConnectRedstone(side))
         {
             if(p.isInstanceOf[IFaceRedstonePart])
-                return 1<<rotationTo(side&6, p.asInstanceOf[IFaceRedstonePart].getFace)
+            {
+                val fside = p.asInstanceOf[IFaceRedstonePart].getFace
+                if((side&6) == (fside&6))
+                    return 0x10
+                
+                return 1<<rotationTo(side&6, fside)
+            }
             return 0x1F
         }
         return 0

codechicken/multipart/TileMultipart.scala

@@ -261,6 +261,7 @@ class TileMultipart extends TileEntity
         
         partRemoved(part, r)
         part.onRemoved()
+        part.tile = null
         
         if(partList.isEmpty)
         {

codechicken/multipart/handler/Proxies.scala

@@ -94,6 +94,6 @@ object MultipartProxy extends MultipartProxy_clientImpl
     var block:BlockMultipart = _
     var config:ConfigFile = _
     
-    def indexInChunk(cc:ChunkCoordIntPair, i:Int) = new BlockCoord(cc.chunkXPos<<4|i&0xF, i>>8, cc.chunkZPos<<4|(i&0xF0)>>4)
+    def indexInChunk(cc:ChunkCoordIntPair, i:Int) = new BlockCoord(cc.chunkXPos<<4|i&0xF, (i>>8)&0xFF, cc.chunkZPos<<4|(i&0xF0)>>4)
     def indexInChunk(pos:BlockCoord) = pos.x&0xF|pos.y<<8|(pos.z&0xF)<<4
 }