rename some standalone projects

projects/_standalone/nat-flixel-playground/source/import.hx

@@ -0,0 +1,16 @@
+import flixel.FlxGame;
+import openfl.display.Sprite;
+import flixel.FlxState;
+import flixel.ui.FlxButton;
+import flixel.FlxG;
+import flixel.FlxSprite;
+import flixel.util.FlxColor;
+import flixel.input.keyboard.FlxKey;
+import flixel.math.FlxPoint;
+import flixel.math.FlxVelocity;
+import flixel.FlxObject;
+import flixel.tile.FlxTilemap;
+import flixel.group.FlxGroup;
+import flixel.tweens.FlxTween;
+import flixel.tweens.FlxEase;
+import kiss.Prelude;