Added destroyCustomPlugin and destroyCorePlugin

Author: photonstorm

src/plugins/PluginCache.js

@@ -174,4 +174,41 @@ PluginCache.removeCustom = function (key)
     }
 };
 
+/**
+ * Removes all Core Plugins.
+ * 
+ * This includes all of the internal system plugins that Phaser needs, like the Input Plugin and Loader Plugin.
+ * So be sure you only call this if you do not wish to run Phaser again.
+ *
+ * @method Phaser.Plugins.PluginCache.destroyCorePlugins
+ * @since 3.12.0
+ */
+PluginCache.destroyCorePlugins = function ()
+{
+    for (var key in corePlugins)
+    {
+        if (corePlugins.hasOwnProperty(key))
+        {
+            delete corePlugins[key];
+        }
+    }
+};
+
+/**
+ * Removes all Custom Plugins.
+ *
+ * @method Phaser.Plugins.PluginCache.destroyCustomPlugins
+ * @since 3.12.0
+ */
+PluginCache.destroyCustomPlugins = function ()
+{
+    for (var key in customPlugins)
+    {
+        if (customPlugins.hasOwnProperty(key))
+        {
+            delete customPlugins[key];
+        }
+    }
+};
+
 module.exports = PluginCache;