Add 2048-react to open-source demos

Nothing too complicated, but I think it could be a fun beginner demo.
[docs] Update Flux TodoMVC Tutorial
[docs] fix nits
[docs] remove redundant paragraph
Docs: renamed input's state to `message`

Readers might feel confused with the actual input's `value` attribute.
Merge pull request #2080 from fisherwebdev/master

[docs] Update Flux TodoMVC Tutorial
Fix console warning in LegacyImmutableObject

It does check `hasOwnProperty`, but *after* accessing the field and therefore triggering enumerable getters in modified prototypes.
Add version to legacy factory monitoring
Don't transfer props to mocked empty component

We currently automatically render empty components in place of mocks. However,
we were accidentally transferring the props from the mocked descriptor to the
empty component placeholder. Even children.

This change just cleans that up and should only affect unit tests.
Start warning for JSX on plain functions

Let's also bump the version number for the log so that we can start filtering
out the other logs.
Bumping version to help filtering.
Bumping version to help filtering.
Include vendor/ when running jest tests

Now the two transform tests get run alongside the React core tests.

Test Plan: jest
Enable ES7 spread transform when using --harmony

Test Plan: `echo "var o = {...x};" | bin/jsx --harmony` outputs `var o = Object.assign({},x);`.
Merge pull request #2118 from spicyj/es7-spread

Enable ES7 spread transform when using --harmony
Merge pull request #2117 from spicyj/jest-vendor

Include vendor/ when running jest tests
added production example

Addition note: Scribbler.co uses an infinite.js/UITableView like rendering pattern with animations which is only possible because of React.
Merge pull request #2119 from naman34/patch-1

added production example
Merge pull request #2075 from IvanVergiliev/patch-1

Add 2048-react to open-source demos
Merge pull request #2091 from julen/docs/LinkedState

Docs: renamed input's state to `inputValue`