Use correct syntax from React's getting started page [1].

Since the jsx comment wasn't on the first line, the transformer wasn't running [2].

Also removed `require('react-tools')` because a) it's on the tutorial page b) it's not required c) it will cause a ReferenceError when loaded by an HTML page because `require is not defined`.

[1] http://facebook.github.io/react/docs/getting-started.html
[2] /** @jsx React.DOM */ is required. The comment parser is very strict right now; in order for it to pick up the @jsx modifier, two conditions are required. The @jsx comment block must be the first comment on the file. The comment must start with /** (/* and // will not work). If the parser can't find the @jsx comment, it will output the file without transforming it.
Add HTML file. Change README.txt to .md. Add instructions to README.