Add readme file.

README.md

+SwiftShader
+==========
+
+Introduction
+-----------------
+
+SwiftShader is a high-performance CPU-based implementation of the OpenGL ES and Direct3D 9 graphics APIs<sup>1</sup><sup>2</sup>. Its goal is to provide hardware independence for advanced 3D graphics.
+
+Usage
+--------
+
+The SwiftShader libraries act as drop-in replacements for graphics drivers.
+
+On Windows, most applications can be made to use SwiftShader's DLLs by placing them in the same folder as the executable. On Linux, the LD\_LIBRARY\_PATH environment variable or -rpath linker option can be used to direct applications to search for shared libraries in the indicated directory first.
+
+Contributing
+-----------------
+
+See CONTRIBUTING.txt for important contributing requirements.
+
+The canonical repository for SwiftShader is hosted at
+https://swiftshader.googlesource.com/SwiftShader
+
+All changes must be reviewed and approved in the Gerrit review tool at
+https://swiftshader-review.googlesource.com
+
+All changes require a Change-ID tag in the commit message. A commit hook may be used to add this tag automatically, and can be found at:
+https://gerrit-review.googlesource.com/tools/hooks/commit-msg. To clone the repository and install the commit hook in one go: 
+
+    git clone https://swiftshader.googlesource.com/SwiftShader && (cd SwiftShader && curl -Lo `git rev-parse --git-dir`/hooks/commit-msg https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x `git rev-parse --git-dir`/hooks/commit-msg)
+
+Changes are uploaded to Gerrit by performing
+
+    git push origin HEAD:refs/for/master
+
+Contact
+-----------
+
+Public mailing list: swiftshader@googlegroups.com
+
+License
+----------
+
+The SwiftShader project is licensed under the Apache License Version 2.0. You can find a copy of it in LICENSE.txt.
+
+Files in the third_party folder are subject to their respective license.
+
+Authors and Contributors
+-----------------------------------
+
+The legal authors for copyright purposes are listed in AUTHORS.txt.
+
+CONTRIBUTORS.txt contains a list of names of individuals who have contributed to SwiftShader. If you're not on the list, but you've signed the Google CLA and have contributed more than a formatting change, feel free to request to be added.
+
+Disclaimer
+---------------
+
+1. Trademarks are the property of their respective owners.
+2. We do not claim official conformance with any graphics APIs at this moment.
+3. This is not an official Google product.
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