Move hasOwnProperty into helper
Edit doc comments
[changed] Relaxed MemoryStore invariant
[added] RouteStore#registerChildren
[fixed] Active state on <Link>s with key prop

Fixes #211
Trivial missing comma in RouteStore

as reported by the jsx compiler when attempting to pack things up:
```
ERROR in ./~/react-router/modules/stores/RouteStore.js
Module build failed: Error: Parse Error: Line 108: Unexpected identifier
    at throwError (.../node_modules/jsx-loader/node_modules/react-tools/node_modules/esprima-fb/esprima.js:2278:21)
    at throwUnexpected (.../node_modules/jsx-loader/node_modules/react-tools/node_modules/esprima-fb/esprima.js:2322:13)
```
I hope this helps
Merge pull request #212 from hmalphettes/master

Trivial missing comma in RouteStore
[added] Router.renderRoutesToString

[fixed] Initial render to null causing second render
[fixed] Query not passed to willTransitionTo
[fixed] ActiveState mixin causing second render
[added] Docs

```js
Router.renderRoutesToString(routes, originalUrl).then(function (data) {
data.html; //string returned from React.renderComponentToString
}).catch(function (error){
//Redirect will set error.status and error.location
error.status; //302 for Redirect
error.location; //location to redirect to
});
```
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