Simpler CONTRIBUTING suggested by @WestLangley. Fixes mrdoob#2847.

Author: mrdoob

CONTRIBUTING.md

@@ -1,23 +1,27 @@
 # The issues section is for bug reports and feature requests only. If you need help, please use [stackoverflow](http://stackoverflow.com/questions/tagged/three.js).
 
-## How to report a bug?
 
-* Tell us the revision number of three.js you use.
-* Try checking your application with the latest `dev` branch version of three.js (often problems are already fixed there). See [migration guide](https://github.com/mrdoob/three.js/wiki/Migration).
-* Tell us where did you observe the problem: your browser version, your operating system, your graphics card (for example Chrome 23.0.1271.95, Windows 7, Nvidia Quadro 2000M)
-* If you can, try to check your problem on multiple browsers / multiple computers (if you are on Windows, especially helpful is to [compare ANGLE and OpenGL renderers](https://github.com/mrdoob/three.js/wiki/How-to-use-OpenGL-or-ANGLE-rendering-on-Windows))
-* Describe the problem in details (what you get instead of what's expected). Saying "it doesn't work" doesn't help much.
-* Create a small testcase (big chance is when you do this, you'll find the answer yourself).
-* If small testcase is not possible, at least include a link to online live version of your application.
-* If your problem creates some visual glitch it helps to include a screenshot (highlight problematic area if problem is subtle).
-* What did you try already?
-* Search issue tracker for similar issues. Somebody else may have already filled an issue about your problem (in that case make a comment there instead of creating new issue). Or there may be other issues that seem similar, it helps if you can cross-reference them (mentioned in text hashed issue number like this `#1234`).
+Before reporting a bug
+---
+1. Search issue tracker for similar issues.
+2. Try the latest dev branch version of three.js.
+3. Refer to the [Migration Guide](https://github.com/mrdoob/three.js/wiki/Migration) when upgrading to the dev version.
 
-## How to contribute to three.js?
 
-* Make sure you have a GitHub account.
-* Fork the repository on GitHub.
-* Check [contribution guidelines](https://github.com/mrdoob/three.js/wiki/How-to-contribute-to-three.js).
-* Make changes to your clone of the repository.
-* Submit a pull request.
+How to report a bug
+---
+1. Specify the revision number of the three.js library where the bug occurred.
+2. Specify your browser version, operating system, and graphics card. (for example, Chrome 23.0.1271.95, Windows 7, Nvidia Quadro 2000M)
+3. Describe the problem in detail. Explain what happened, and what you expected would happen.
+4. Provide a small test-case (http://jsfiddle.net). If a test-case is not possible, provide a link to a live version of your application.
+5. If helpful, include a screenshot. Annotate the screenshot for clarity.
+
+
+How to contribute to three.js
+---
+1. Make sure you have a GitHub account.
+2. Fork the repository on GitHub.
+3. Check the [Contribution Guidelines](https://github.com/mrdoob/three.js/wiki/How-to-contribute-to-three.js).
+4. Make changes to your clone of the repository.
+5. Submit a pull request.