Libgdx Scene2d Skin quick tutorial

This post shows a brief introduction to using Skins in your Scene2d project. It's very useful to use a JSON file that declares all the styles for your Scene2d elements, but it can be counter-intuitive at the beginning.
[null, {"document_url": "http://pimentoso.blogspot.com/2013/04/libgdx-scene2d-skin-quick-tutorial.html", "unformatted_src": "http://3.bp.blogspot.com/-neAzb_Q5K2c/UVstzSklHLI/AAAAAAAAB44/2iP6-IyfB0A/s320/Untitled-4.png", "src": "http://3.bp.blogspot.com/-neAzb_Q5K2c/UVstzSklHLI/AAAAAAAAB44/2iP6-IyfB0A/s320/Untitled-4.png", "formatted_filename": "Untitled", "rendered_width": 320, "rendered_height": 207}, {"document_url": "http://pimentoso.blogspot.com/2013/04/libgdx-scene2d-skin-quick-tutorial.html", "unformatted_src": "http://2.bp.blogspot.com/-WkCtpJY7vl4/UVsrz_BAn5I/AAAAAAAAB4o/zBJhnAthr9c/s320/Untitled-2.png", "src": "http://2.bp.blogspot.com/-WkCtpJY7vl4/UVsrz_BAn5I/AAAAAAAAB4o/zBJhnAthr9c/s320/Untitled-2.png", "formatted_filename": "Untitled", "rendered_width": 320, "rendered_height": 284}, {"document_url": "http://pimentoso.blogspot.com/2013/04/libgdx-scene2d-skin-quick-tutorial.html", "unformatted_src": "http://2.bp.blogspot.com/-mRGFpc5VoOs/UVssVOa6ZpI/AAAAAAAAB4w/Rx4WAp9KF2I/s320/Untitled-3.png", "src": "http://2.bp.blogspot.com/-mRGFpc5VoOs/UVssVOa6ZpI/AAAAAAAAB4w/Rx4WAp9KF2I/s320/Untitled-3.png", "formatted_filename": "Untitled", "rendered_width": 320, "rendered_height": 265}, null, null, null, null, null, null, null]