add upgrade slots

src/api/java/appeng/api/implementations/IUpgradeableCellContainer.java

@@ -0,0 +1,7 @@
+package appeng.api.implementations;
+
+public interface IUpgradeableCellContainer {
+    int availableUpgrades();
+
+    void setupUpgrades();
+}

src/api/java/appeng/api/implementations/IUpgradeableCellHost.java

@@ -0,0 +1,41 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013 AlgorithmX2
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package appeng.api.implementations;
+
+
+import appeng.api.config.Upgrades;
+import appeng.api.implementations.tiles.ISegmentedInventory;
+import appeng.api.util.IConfigurableObject;
+
+
+public interface IUpgradeableCellHost extends IConfigurableObject, ISegmentedInventory {
+
+    /**
+     * determine how many of an upgrade are installed.
+     */
+    default int getInstalledUpgrades(Upgrades u) {
+        return 0;
+    }
+
+}