Fixed Haxe3 + FLixel 2.55 imports

Hello.

Using directly the library show some import errors with Flixel 255 and Haxe 3. THe imports are wrong and needed to be fixed to make LevelTools work.

I just replaced  these line:
> import flixel.{subpackage}.{class};

Into these:
> import org.flixel.{class};

Have a nice day.