[Versions] Update versions in package.json and podspec to 0.7.1

Summary:
When developing against master I want to rely on the version numbers being reasonably accurate.
Closes https://github.com/facebook/react-native/pull/1804
Github Author: James Ide <ide@jameside.com>

React.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name                = "React"
-  s.version             = "0.4.2"
+  s.version             = "0.8.0"
   s.summary             = "Build high quality mobile apps using React."
   s.description         = <<-DESC
                             React Native apps are built using the React JS

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-native",
-  "version": "0.6.0",
+  "version": "0.8.0",
   "description": "A framework for building native apps using React",
   "license": "BSD-3-Clause",
   "repository": {