dillon1000/react

Warn when server-rendered markup is not what we expect on the client

As @leebyron and balpert pointed out, if the markup on the server is differnet than what the client expects undefined behavior and chaos may ensue. A good fallback
is for us to just inject the client-side markup (as it is the source of truth) and warn the user in __DEV__ that something is wrong. In order to do a fast
browser-independent check of the DOM I use an adler32 checksum of the generated markup. I believe this is better than a simple innerHTML compare because different
browsers massage innerHTML differently.