Added registerable implementations of CommandExecutor and Listener

src/main/kotlin/net/axay/kspigot/utils/RegisterableCommand.kt

@@ -0,0 +1,26 @@
+package net.axay.kspigot.utils
+
+import net.axay.kspigot.main.KSpigot
+import org.bukkit.command.CommandExecutor
+import org.bukkit.command.TabCompleter
+
+interface RegisterableCommand : CommandExecutor {
+
+    /**
+     * Registers this executor for the given command
+     * and for the given instance of [kSpigot].
+     *
+     * @return true if the command was found -
+     * false if not
+     */
+    fun registerCommand(commandName: String, kSpigot: KSpigot): Boolean {
+        kSpigot.plugin.getCommand(commandName)?.let {
+            it.setExecutor(this)
+            if (this is TabCompleter)
+                it.tabCompleter = this
+            return true
+        }
+        return false
+    }
+
+}

src/main/kotlin/net/axay/kspigot/utils/RegisterableListener.kt

@@ -0,0 +1,15 @@
+package net.axay.kspigot.utils
+
+import net.axay.kspigot.main.KSpigot
+import org.bukkit.Bukkit
+import org.bukkit.event.Listener
+
+interface RegisterableListener : Listener {
+
+    /**
+     * Registers this listener
+     * for the given instance of [kSpigot].
+     */
+    fun registerListener(kSpigot: KSpigot) = Bukkit.getPluginManager().registerEvents(this, kSpigot.plugin)
+
+}