title: Spritesheet creator/importer for unity3d
body: <p>I am currently developing a 2d game for android using Unity3d , but i am wondering if is there any free sprite sheet creator software that is compatible with unity3d without the extra code to be written , i've tried <code>texture packer</code> with there plugin for unity and it work great but this software is paid and i can not afford it right now ,
  i also tried <code>Sprite Sheet Packer</code> but when i import the sprite sheet into unity and trim the sprites in the editor the animation does not work properly due to the fact that unity did not know the pivot point and the exact information of the sprite inside the created sprite sheet,
  Does anyone know some useful free software that i can use or some unity plugin that can serve this problem ?     </p>