Try to fix energy overflow (#114)

src/main/java/crazypants/enderio/item/ItemMagnet.java

@@ -131,6 +131,10 @@ public class ItemMagnet extends ItemEnergyContainer implements IResourceTooltipP
 
     @Override
     public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        if (maxReceive < 0) {
+            return 0;
+        }
+
         int res = super.receiveEnergy(container, maxReceive, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);
@@ -148,6 +152,10 @@ public class ItemMagnet extends ItemEnergyContainer implements IResourceTooltipP
     }
 
     public int extractEnergyInternal(ItemStack container, int maxExtract, boolean simulate) {
+        if (maxExtract < 0) {
+            return 0;
+        }
+
         int res = super.extractEnergy(container, maxExtract, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);

src/main/java/crazypants/enderio/teleport/ItemTeleportStaff.java

@@ -67,6 +67,12 @@ public class ItemTeleportStaff extends ItemTravelStaff {
         return equipped;
     }
 
+    @Override
+    public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        // Don't allow receiving energy, since we have infinite energy.
+        return 0;
+    }
+
     @Override
     public int extractEnergy(ItemStack container, int maxExtract, boolean simulate) {
         // Don't allow extracting energy.

src/main/java/crazypants/enderio/teleport/ItemTravelStaff.java

@@ -103,6 +103,10 @@ public class ItemTravelStaff extends ItemEnergyContainer implements IItemOfTrave
 
     @Override
     public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        if (maxReceive < 0) {
+            return 0;
+        }
+
         int res = super.receiveEnergy(container, maxReceive, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);
@@ -112,6 +116,10 @@ public class ItemTravelStaff extends ItemEnergyContainer implements IItemOfTrave
 
     @Override
     public int extractEnergy(ItemStack container, int maxExtract, boolean simulate) {
+        if (maxExtract < 0) {
+            return 0;
+        }
+
         int res = super.extractEnergy(container, maxExtract, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);