update docs to point to git-pull.com

Author: tony

README.rst

@@ -181,7 +181,7 @@ Project details
 tmux support    1.8, 1.9a, 2.0, 2.1, 2.2
 python support  2.6, 2.7, >= 3.3
 Source          https://github.com/tony/libtmux
-Docs            http://libtmux.rtfd.org
+Docs            http://libtmux.git-pull.com
 API             http://libtmux.git-pull.com/api.html
 Changelog       http://libtmux.git-pull.com/history.html
 Issues          https://github.com/tony/libtmux/issues