add a copy/paste chat sample and some re-shuffling of the other apps

Summary:

* replace `chat2` with a clone of Matt's copy/paste sample from `uproxy-networking`
* `freedomchat-chromeapp` really didn't need to be a Chrome app -- make it a web page
* rename `freedomchat-webpage` -> `freedom-chat-webpage`
Can the name "handleChatMessage" change to be clear about whether the message is incoming or outgoing?  (Bonus points for naming the event as a noun / noun phrase, for consistency with most other event names.)