Bump to react 15.4

Add dependencies on react 15.4. Some of the things we pull in from
matrix-react-sdk won't work properly against 15.2 / 15.0.

package.json

@@ -70,10 +70,10 @@
     "matrix-react-sdk": "matrix-org/matrix-react-sdk#develop",
     "modernizr": "^3.1.0",
     "q": "^1.4.1",
-    "react": "^15.2.1",
+    "react": "^15.4.0",
     "react-dnd": "^2.1.4",
     "react-dnd-html5-backend": "^2.1.2",
-    "react-dom": "^15.2.1",
+    "react-dom": "^15.4.0",
     "react-gemini-scrollbar": "matrix-org/react-gemini-scrollbar#5e97aef",
     "sanitize-html": "^1.11.1",
     "ua-parser-js": "^0.7.10",
@@ -115,8 +115,8 @@
     "mocha": "^2.4.5",
     "parallelshell": "^1.2.0",
     "phantomjs-prebuilt": "^2.1.7",
-    "react-addons-perf": "^15.0",
-    "react-addons-test-utils": "^15.0.1",
+    "react-addons-perf": "^15.4.0",
+    "react-addons-test-utils": "^15.4.0",
     "rimraf": "^2.4.3",
     "source-map-loader": "^0.1.5",
     "webpack": "^1.12.14",