React

• Improve performance of development builds in various ways. (@gaearon in #7461, #7463, #7483, #7488, #7491, #7510)
• Cleanup internal hooks to improve performance of development builds. (@gaearon in #7464, #7472, #7481, #7496)
• Upgrade fbjs to pick up another performance improvement from @gaearon for development builds. (@zpao in #7532)
• Improve startup time of React in Node. (@zertosh in #7493)
• Improve error message of React.Children.only. (@spicyj in #7514)

React DOM

• Avoid <input> validation warning from browsers when changing type. (@nhunzaker in #7333)
• Avoid "Member not found" exception in IE10 when calling stopPropagation() in Synthetic Events. (@nhunzaker in #7343)
• Fix issue resulting in inability to update some <input> elements in mobile browsers. (@keyanzhang in #7397)
• Fix memory leak in server rendering. (@keyanzhang in #7410)
• Fix issue resulting in <input type="range"> values not updating when changing min or max. (@troydemonbreun in #7486)
• Add new warning for rare case of attempting to unmount a container owned by a different copy of React. (@ventuno in #7456)

React Test Renderer

• Fix ReactTestInstance::toJSON() with empty top-level components. (@Morhaus in #7523)

React Native Renderer

• Change trackedTouchCount invariant into a console.error for better reliability. (@yungsters in #7400)