Merge pull request #4846 from zpao/docs-use-babel

[docs] Remove references to react-tools, JSXTransformer, replace with Babel.
(cherry picked from commit d3d2504e72)

docs/css/react.scss

@@ -481,38 +481,6 @@ section.black content {
   padding-bottom: 40px;
 }
 
-/* JSX Compiler */
-
-.jsxCompiler {
-  margin: 0 auto;
-  padding-top: 20px;
-  width: 1220px;
-
-  label.compiler-option {
-    display: block;
-    margin-top: 5px;
-  }
-
-  #jsxCompiler {
-    margin-top: 20px;
-  }
-
-  .playgroundPreview {
-    padding: 0;
-    width: 600px;
-
-    pre {
-      @include code-typography;
-    }
-  }
-
-  .playgroundError {
-    // The compiler view kills padding in order to render the CodeMirror code
-    // more nicely. For the error view, put a padding back
-    padding: 15px 20px;
-  }
-}
-
 /* Button */
 
 .button {