Use classnames instead of react/lib/cx.

classSet / cx will be removed in a future version of React.

See also:
facebook/react@b6980ab

Author: peterjmag

Diff for: lib/components/ModalPortal.js

@@ -2,7 +2,7 @@ var React = require('react');
 var div = React.DOM.div;
 var focusManager = require('../helpers/focusManager');
 var scopeTab = require('../helpers/scopeTab');
-var cx = require('react/lib/cx');
+var cx = require('classnames');
 
 // so that our CSS is statically analyzable
 var CLASS_NAMES = {

Diff for: package.json

@@ -40,9 +40,9 @@
     "webpack-dev-server": "1.6.5"
   },
   "peerDependencies": {
-    "react": ">=0.12.0"
+    "react": ">=0.12.0",
+    "classnames": "^1.2.0"
   },
-  "dependencies": {},
   "tags": [
     "react",
     "modal",