Update README.md
Merge branch 'master' of https://github.com/newnon/Cheetah-Texture-Packer

* 'master' of https://github.com/newnon/Cheetah-Texture-Packer:
  --border-size              set border size in pixels\n\ --extrude-size             set extrude size in pixels\n\

Conflicts:
	README.md