Plugin manager, misc fixes

* Fixed an error when trying to create nonexisting resource type
* Updated the init-command to create plugins and scipts directories
* Added a basic installer function

bin/spark

@@ -9,5 +9,10 @@ else {
 
 require_once __DIR__."/../vendor/autoload.php";
 
+if ($argc == 2 && $argv[1] === "install") {
+    require_once __DIR__."/../src/install";
+    exit(0);
+}
+
 $app = new Spark\SparkApplication();
 $app->run();